Electrically-powered surgical systems with articulation-compensated ultrasonic energy delivery

ABSTRACT

Surgical systems and methods are provided for controlling actuation and movement of various surgical devices.

FIELD

Electrically-powered surgical systems and methods for using the same areprovided for cutting or dissecting tissue.

BACKGROUND

More and more surgical procedures are being performed usingelectrically-powered surgical devices that are either hand-held or thatare coupled to a surgical robotic system. Such devices generally includeone or more motors for driving various functions on the device, such asshaft rotation, articulation and actuation of an end effector, and oneor more generators for delivery of energy.

A common concern with electrically-powered surgical devices is arelative lack of c haptic feedback. Mechanically-powered surgicaldevices can have articulating features (e.g., jaws, blades, etc.)powered by user actuation of actuatable objects such as triggers, knobs,etc. These mechanically-powered surgical devices can inherently providea high degree haptic feedback because device actuation is completelyreliant upon the movements of the user and mechanical linkages betweenarticulating features and actuatable objects can provide force-feedback.However, this direct connection between user movements and surgicaldevice actuation is not present in electrically-powered devices, wherearticulating features can be moved by electrically-powered motors inresponse to actuation of low-feedback actuatable objects, such asbuttons. Thus, reliance upon haptic feedback to assess the state ofsurgical functions (e.g., progress of cutting operations, clampingforces applied to tissue, etc.) can be significantly impaired inelectrically-powered surgical devices as compared tomechanically-powered surgical devices.

Accordingly, there remains a need for improved devices and methods thataddress current issues with electrically-powered surgical devices.

SUMMARY

Surgical systems and methods for using the same are provided herein.

In one exemplary embodiment, a surgical system is provided and caninclude a surgical tool and a control system. The surgical tool caninclude a shaft and an end effector formed at a distal end thereof. Theend effector can have a clamping element and an ultrasonic blade and itcan be configured to clamp and treat tissue disposed between theclamping element and the ultrasonic blade. The control system can beconfigured to variably control a clamping force applied to tissuedisposed between the clamping element and the ultrasonic blade accordingto one or more control modes before transmission of ultrasonicvibrations to the ultrasonic blade to coagulate and/or cut the tissue.The clamping force can range between a maximum clamping force (F_(max))and a minimum clamping force (F_(min)).

Embodiments of the control system can have a variety of configurations.In one aspect, the control system can be configured to apply theclamping force to tissue over a first predetermined clamping time(t_(c1)) in a first control mode. The first control mode can occurbefore transmission of ultrasonic vibrations to the ultrasonic blade andit can include gradually increasing the clamping force from F_(min) toF_(max). In another aspect, the control system can be configured tomaintain application of F_(max) to tissue for a second predeterminedclamping time (t_(c2)) in a second control mode. The second control modecan occur immediately after the first control mode and prior totransmission of ultrasonic vibrations to the ultrasonic blade. Inanother aspect, the control system can be configured to concurrentlyapply the clamping force to tissue and ultrasonic vibrations to theblade for a predetermined treatment time (t_(t)) in a third controlmode. The third control mode can occur immediately after the secondcontrol mode and it can include applying a treatment clamping force(F_(treat)) between F_(min) and F_(max). In another aspect, the controlsystem can be configured to vary a peak amplitude of ultrasonic wavestransmitted to the ultrasonic blade between a maximum amplitude(A_(max)) and a minimum amplitude (A_(min)) during the third controlmode. In another aspect, an amplitude (A₁) between A_(max) and A_(min)can be transmitted for a first portion of the predetermined treatmenttime t_(t1) and A_(min) can be transmitted immediately thereafter for asecond portion of the predetermined treatment time t_(t2). In anotheraspect, the amplitude can be increased from the A₁ to A_(max)immediately following t_(t2).

In another exemplary embodiment, a surgical system is provided and caninclude a surgical tool and a control system. The surgical tool caninclude a shaft and an end effector formed at a distal end thereof. Theend effector can have a clamping element and an ultrasonic blade and itcan be configured to clamp and treat tissue disposed between theclamping element and the ultrasonic blade. The control system can beconfigured to variably control a clamping force applied to tissuedisposed between the clamping element and the ultrasonic blade accordingto one or more control modes during transmission of ultrasonicvibrations to the ultrasonic blade to coagulate and/or cut the tissue.The clamping force can range between a maximum clamping force (F′_(max))and a minimum clamping force (F′_(min)).

Embodiments of the control system can have a variety of configurations.In one aspect, the control system can be configured to apply theclamping force to tissue for a first predetermined clamping time(t′_(c1)) in a first control mode. The first control mode can occurbefore transmission of ultrasonic vibrations to the ultrasonic blade andit can include gradually increasing the clamping force from F′_(min) toa treatment clamping force F′_(treat) between F′_(min) and F′_(max). Inanother embodiment, the control system can be configured to maintainapplication of F′_(treat) to tissue for a second predetermined clampingtime (t′_(c2)) in a second control mode. The second control mode canoccur immediately after the first control mode and before transmissionof ultrasonic vibrations to the ultrasonic blade. In another aspect, thecontrol system can be configured to apply both the clamping force totissue and the ultrasonic vibrations to the ultrasonic blade for apredetermined treatment time (t′_(t)) immediately following the secondcontrol mode. In another aspect, the control system can be configured toapply F_(max) to tissue for a first portion (t′_(t1)) of thepredetermined treatment time t′_(t) in a third control mode. In anotheraspect, an amplitude (A′₁) between a minimum amplitude A′_(max) and amaximum amplitude A′_(min) is transmitted to the blade during the thirdcontrol mode. In another aspect, the control system can be configured toapply F′_(treat) to tissue in a fourth control mode immediately afterthird control mode. In another aspect, an amplitude (A′₂) greater thanA′₁ and less than A′_(max) can be transmitted to the ultrasonic bladefor a second predetermined treatment time (t′_(t2)) immediately aftert′_(t1). In another aspect, A′_(min) can be transmitted to theultrasonic blade for a third predetermined treatment time (t′_(t3))immediately after t′_(t2). In another aspect, A′_(max) can betransmitted to the blade for a fourth predetermined treatment time(t′_(t4)) immediately after t′_(t3).

Methods for treating tissue are also provided. In one embodiment, themethod can include actuating a motor to cause an end effector of asurgical instrument including a clamping element and an ultrasonic bladeto apply a clamping force to tissue disposed between the clampingelement and the ultrasonic blade. The method can also includetransmitting, by an ultrasonic generator, ultrasonic vibrations to theultrasonic blade to coagulate or cut the tissue clamped between theclamping element and the ultrasonic blade. The method can also includevarying, by the motor, the clamping force applied to tissue disposedbetween the clamping element and the ultrasonic blade before or duringtransmission of ultrasonic vibrations to the blade according to one ormore control modes, the clamping force ranging between a maximumclamping force (F_(max)) and a minimum clamping force (F_(min)).

In another embodiment, F_(max) can be applied to the tissue for apredetermined clamping time prior to transmitting ultrasonic vibrationsto the blade.

In another embodiment, a treatment clamping force (F_(treat)) betweenF_(max) and F_(min) can be applied to the tissue for a predeterminedtreatment time during transmission of ultrasonic vibrations to theblade.

In another embodiment, a treatment clamping force (F′_(treat)) betweenF_(max) and F_(min) can be applied to the tissue for a predeterminedclamping time before transmission of ultrasonic vibrations to the blade.F_(max) can be applied to the tissue for a first predetermined treatmenttime during transmission of ultrasonic vibrations to the blade.F_(treat) can be applied to the tissue for a second predeterminedtreatment time during transmission of ultrasonic vibrations to the bladeand after the first predetermined treatment time.

In another exemplary embodiment, a surgical system is provided and caninclude an end effector, a shaft assembly, an interface assembly, and acontrol system. The end effector can have an ultrasonic blade and aclamping element, where the ultrasonic blade can be configured toreceive ultrasonic vibrations from an ultrasonic transducer and theclamping element can be configured to clamp and treat tissue disposedbetween the clamping element and the ultrasonic blade as ultrasonicvibrations are applied to the tissue from the ultrasonic blade. Theshaft assembly can have a longitudinal axis and the end effector can bedisposed at a distal end thereof. The shaft assembly can also include anarticulation section operable to deflect the end effector away at thelongitudinal axis an articulation angle between a minimum articulationangle of about 0 degrees when the end effector is aligned with thelongitudinal axis of the shaft assembly to a maximum non-zeroarticulation angle in either direction when the end effector is notaligned with the longitudinal axis of the shaft assembly. The interfaceassembly can have one or more drive shafts coupled to the end effectorand the shaft assembly configured to drive movement of the end effectorand the shaft assembly. The control system can be configured to controlan amplitude of ultrasonic vibrations received by the ultrasonic bladesuch that the amplitude increases with an increase in the articulationangle of the end effector.

Embodiments of the control system can have a variety of configurations.In one aspect, the control system can be configured to measure rotationof a first drive shaft that is operable to adjust the articulation angleof the end effector. In another aspect, the control system can beconfigured to control the amplitude of the ultrasonic vibrations basedupon the measured rotation of the first drive shaft. In another aspect,the control system can be configured to control the amplitude of theultrasonic vibrations during articulation of the end effector.

In another embodiment, the control system can be configured to control arate of change of the amplitude of the ultrasonic vibrations withrespect to the articulation of the end effector between the minimum andmaximum articulation angles. The rate of change of the amplitude can beapproximately constant between the minimum and maximum articulationangles. Alternatively, the rate of change of the amplitude can varybetween the minimum and maximum articulation angles.

Methods for treating tissue are also provided. In one embodiment, themethod can include actuating a motor to cause a shaft assembly having alongitudinal axis and an end effector disposed at a distal end thereofhaving a clamping element and an ultrasonic blade, to deflect at anarticulation angle between a minimum articulation angle of about 0degrees when the end effector is aligned with the longitudinal axis ofthe shaft assembly and a maximum non-zero articulation angle in eitherdirection when the end effector is not aligned with the longitudinalaxis of the shaft. The method can also include transmitting, by anultrasonic generator, ultrasonic vibrations to the ultrasonic blade tocoagulate or cut tissue clamped between the clamping element and theultrasonic blade. The method can additionally include varying, by theultrasonic generator, an amplitude of the ultrasonic vibrations suchthat the amplitude increases with an increase in the articulation of theend effector.

In another embodiment, the method can include measuring a rotation of adrive shaft coupled to the shaft assembly and configured to drivearticulation of the end effector between the minimum and maximumarticulation angles. The amplitude of the ultrasonic vibrations can bevaried based upon the measured rotation of the drive shaft. Theamplitude of the ultrasonic vibrations can be varied during articulationof the end effector.

In another embodiment, the method can include varying a rate of changeof the amplitude of the ultrasonic vibrations with respect to thearticulation of the end effector between the minimum and maximumarticulation angles. The rate of change of the amplitude can beapproximately constant between the minimum and maximum articulationangles. Alternatively, the rate of change of the amplitude can varybetween the minimum and maximum articulation angles.

In another exemplary embodiment, a surgical system is provided and caninclude a surgical tool, a closure mechanism, and a control system. Thesurgical tool can include a shaft and an end effector formed at a distalend thereof. The end effector can have a clamping element and anultrasonic blade. The clamping element can be movable relative to theultrasonic blade to clamp and treat tissue disposed between the clampingelement and the ultrasonic blade. The closure mechanism can beconfigured to selectively move the clamping element towards theultrasonic blade from an open configuration to a closed configuration ata predetermined clamping velocity (v_(c)). The control system can beconfigured to maintain v_(c) at a first clamping velocity (v_(c1))greater than a minimum clamping velocity (v_(min)) until a predeterminedclamping force threshold (F_(o)) is achieved. The control system canalso be configured to determine a closure parameter including at leastone of an amount of time required to reach F_(o) and an amount ofdisplacement of the clamping element required to achieve F_(o). Thecontrol system can additionally be configured to determine a tissuecharacteristic based upon the closure parameter. The control system canalso be configured to deliver energy to the ultrasonic blade to treattissue in a feathering treatment according to a feathering treatmentprotocol based upon the determined tissue characteristic.

In another embodiment, F_(o) can be a force resulting from contact ofthe clamping element with a tissue disposed between the clamping elementand the ultrasonic blade.

In another embodiment, the feathering treatment can be effective tocoagulate a tissue disposed between the clamp arm and the ultrasonicblade.

In another embodiment, the tissue characteristic can be a thickness of atissue disposed between the clamping element and the ultrasonic blade.

In another embodiment, when the tissue thickness is less than apredetermined thickness, the control system can be configured to operatein the feathering treatment protocol by maintaining v_(c) at a thirdclamping velocity (v_(c3)) while a clamping force applied to tissuedisposed between the clamp arm and the ultrasonic blade is less than apredetermined second treatment force (F₂). The control system can alsobe configured to operate in the feathering treatment protocol bydecreasing v_(c) from v_(c3) to a fourth clamping velocity (v_(c4)) forthe remainder of the feathering treatment in response to the clampingforce rising to F₂, where v_(c4) can be configured to maintain theclamping force below F₂. v_(c3) and v_(c4) can each be approximatelyconstant.

In another embodiment, when the tissue thickness is greater than apredetermined thickness, the control system can be configured to operatein the feathering treatment protocol by applying a clamping force totissue disposed between the clamp arm and the ultrasonic blade at anapproximately constant first treatment force (F₁). The control systemcan also be configured to allow v_(c) to decrease to a levelapproximately equal to v_(min) and increase the clamping force to alevel between F₁ and a less than a second treatment force (F₂) for theremainder of the feathering treatment. F₁ can be based upon thedetermined tissue characteristic.

In another embodiment, the system can include an electrode configured todeliver radiofrequency energy to a tissue disposed between the clampingelement and the ultrasonic blade. The control system can be configuredto deliver at least one of ultrasonic energy to the ultrasonic blade andradiofrequency energy to the electrode according to a sealing treatmentprotocol occurring after the feathering treatment for coagulating andcutting a tissue disposed a tissue disposed between the clamping elementand the ultrasonic blade.

In another embodiment, the control system can be configured to performthe sealing treatment in response to detection that a preselectedtrigger condition is satisfied. In one aspect, the trigger condition canbe movement of the clamping element to a predetermined distance from theultrasonic blade. In another aspect, the trigger condition can bedeviation of v_(c) from a velocity set point by a predetermined velocitythreshold. In another aspect, the trigger condition can be applicationof a clamping force at a predefined amount of a maximum clamping forceF_(max).

Methods for treating tissue are also provided. In one embodiment, themethod can include actuating a motor of a surgical tool including ashaft and an end effector. The end effector can be formed at a distalend of the shaft and it can have a clamping element and an ultrasonicblade coupled to an ultrasonic transducer. The clamping element can bemoveable relative to the ultrasonic blade to a tissue clamping positionbetween an open position and a closed position of the clamping elementat a predetermined clamping velocity (v_(c)). The method can alsoinclude maintaining v_(c) at a first clamping velocity (v_(c1)) greaterthan a minimum clamping velocity (v_(min)) until a predeterminedclamping force threshold (F_(o)) is achieved. The method can alsoinclude determining a closure parameter including at least one of anamount of time (t_(c)) required to reach F_(o) and an amount ofdisplacement of the clamping element δ_(c) required to achieve F_(o).The method can also include determining a tissue characteristic basedupon the closure parameter. The method can also include deliveringenergy to the ultrasonic blade to treat tissue in a feathering treatmentaccording to a feathering treatment protocol based upon the determinedtissue characteristic.

In another embodiment, F_(o) can be a force resulting from contact ofthe clamping element with a tissue disposed between the clamping elementand the ultrasonic blade.

In another embodiment, the feathering treatment can be effective tocauterize a tissue disposed between the clamp arm and the ultrasonicblade.

In another embodiment, the tissue characteristic can be a thickness of atissue disposed between the clamping element and the ultrasonic blade.

In another embodiment, the method can include determining the tissuethickness to be less than a predetermined thickness. The method can alsoinclude maintaining v_(c) at a third clamping velocity (v_(c3)) while aclamping force applied to tissue disposed between the clamp arm and theultrasonic blade is less than a predetermined second treatment force(F₂). The method can also include decreasing v_(c) from v_(c3) to afourth clamping velocity (v_(c4)) for the remainder of the featheringtreatment in response to the clamping force rising to F₂, wherein v_(c4)is configured to maintain the clamping force below F₂. v_(c3) and v_(c4)can each be approximately constant.

In another embodiment, the method can include determining the tissuethickness to be greater than a predetermined thickness and applying afirst treatment force F₁ to tissue disposed between the clamp arm andthe ultrasonic blade. The method can also include allowing v_(c) todecrease to a level approximately equal to v_(min) and increasing thefirst treatment force to a level between F₁ and a second treatment forceF₂ for the remainder of the feathering treatment. F₁ can be based uponthe determined tissue characteristic.

In another embodiment, the method can include delivering radiofrequencyenergy to a tissue disposed between the clamping element and theultrasonic blade during the feathering treatment. An amplitude of eachof the ultrasonic and radiofrequency energies can be approximatelyconstant during the feathering treatment. The method can also includedelivering at least one of ultrasonic energy and radiofrequency energyto treat the tissue in a sealing treatment occurring after thefeathering treatment according to a sealing treatment protocol, thesealing treatment configured to coagulate and cut the tissue.

In another embodiment, the method can include performing the sealingtreatment in response to detection that a preselected trigger conditionis satisfied. In one aspect, the trigger condition can be movement ofthe closure mechanism to a predetermined distance from the ultrasonicblade. In another aspect, the trigger condition can be deviation ofv_(c) from a velocity set point by a predetermined velocity threshold.In another aspect, the trigger condition can be application of aclamping force at a predefined amount of a maximum clamping forceF_(max).

In another exemplary embodiment, a surgical system is provided and caninclude a surgical tool, a closure mechanism, a motor, and a controlsystem. The surgical tool can include a shaft and an end effector formedat a distal end thereof. The end effector can have a clamping elementand an ultrasonic blade operably coupled to an ultrasonic transducer.The clamping element can be movable relative to the ultrasonic blade toclamp tissue disposed between the clamping element and the ultrasonicblade such that a first tissue treatment is effected upon energizing theultrasonic blade. The closure mechanism can be configured to selectivelydisplace the clamping element from an initial, open position to a tissueclamping position. The motor can be operably coupled to the closuremechanism. The control system can be in communication with the motor andit can be configured to dynamically control a predetermined tissueclamping force applied to a tissue disposed between the clamping elementand the ultrasonic blade within a desired range between a minimumtreatment force and a maximum treatment force during the first tissuetreatment to respond to changes in the tissue as a result of the firsttissue treatment.

In another embodiment, the control system can be configured to control aposition of the clamping element in response to receipt of a commandedposition when the clamping force applied to tissue is less than theminimum treatment force and the clamping element is distanced by greaterthan a predetermined minimum amount from the closed position.

In another embodiment, the control system can be configured todynamically control the position of the clamping element to maintain thepredetermined tissue clamping force when the clamping force applied totissue exceeds the minimum treatment force or the clamping element isdistanced by less than a predetermined minimum amount from the closedposition. The control system can also be configured to control a motortorque within a predetermined range to maintain the tissue clampingforce within the desired range during the first tissue treatment. Thecontrol system can also be configured to control an amount of currentdelivered to the motor to control the motor torque.

In another embodiment, the system can include an electrode coupled tothe clamping element and operatively coupled to a radiofrequencygenerator. The electrode can be configured to provide a second tissuetreatment to the tissue disposed between the clamping element and theultrasonic blade when receiving radiofrequency energy from theradiofrequency generator.

In another embodiment, the control system can be configured to determinea position of the clamping element with respect to the closed positionand allow delivery of radiofrequency energy less than a predeterminedthreshold energy to the electrode when the position of the clampingelement is distanced by greater than a predetermined amount from theclosed position.

In another embodiment, the control system can be configured to determinea position of the clamping element with respect to the closed positionand allow delivery of radiofrequency energy greater than a predeterminedthreshold energy to the electrode when the position of the clampingelement is distanced by less than a predetermined amount from the closedposition.

In another embodiment, the control system can be configured to determinea position of the clamping element with respect to the closed positionand inhibit delivery of radiofrequency energy greater than apredetermined threshold energy to the electrode when the clampingelement is distanced by greater than a predetermined minimum distancefrom the closed position. The control system can also be configured totrigger an alert to position the clamping element at a distance lessthan the predetermined minimum distance to allow delivery ofradiofrequency energy greater than the predetermined threshold energy tothe electrode.

Methods for treating tissue are also provided. In one embodiment, themethod can include actuating a motor of a surgical tool including ashaft and an end effector. The end effector can be formed at a distalend of the shaft and it can include a clamping element and an ultrasonicblade coupled to an ultrasonic transducer. The clamping element can bemoveable relative to the ultrasonic blade to a tissue clamping positionbetween an open position and a closed position of the clamping elementin response to the motor actuation. The method can also includeadjusting the position of the clamping element using the motor to afirst tissue clamping position where the clamping element applies aclamping force approximately equal to a predetermined minimum treatmentclamping force. The method can also include transmitting ultrasonicenergy from the ultrasonic transducer to the ultrasonic blade after theapplied clamping force is greater than or equal to the minimum treatmentclamping force. The method can also include adjusting the position ofthe clamping element using the motor to apply a target clamping forcebetween the minimum treatment clamping force and a predetermined maximumtreatment clamping force while ultrasonic energy is transmitted to theultrasonic blade.

In another embodiment, the method can include controlling a position ofthe clamping element in response to receipt of a commanded position whenthe clamping force applied to tissue is less than the minimum treatmentforce and the position of the clamping element is distanced by greaterthan a predetermined minimum amount from the closed position.

In another embodiment, the method can include dynamically controllingthe position of the clamping element to maintain the target clampingforce when the clamping force exceeds the minimum treatment force or theclamping element is distanced by less than a predetermined minimumamount from the closed position. The method can also include controllinga motor torque within a predetermined range to maintain the tissueclamping force within the desired range during the first tissuetreatment. The method can also include controlling an amount of currentdelivered to the motor to control the motor torque.

In another embodiment, the method can include delivering radiofrequencyenergy to an electrode coupled to the clamping element.

In another embodiment, the method can include determining a position ofthe clamping element with respect to the closed position and deliveringradiofrequency energy less than a predetermined threshold energy to theelectrode when the position of the clamping element is distanced bygreater than a predetermined amount from the closed position.

In another embodiment, the method can include determining a position ofthe clamping element with respect to the closed position and deliveringof radiofrequency energy greater than a predetermined threshold energyto the electrode when the position of the clamping element is distancedby less than a predetermined amount from the closed position.

In another embodiment, the method can include determining a position ofthe clamping element with respect to the closed position and inhibitingdelivery of radiofrequency energy greater than a predetermined thresholdenergy to the electrode when the clamping element is distanced bygreater than a predetermined minimum distance from the closed position.The method can also include triggering an alert to position the clampingelement at a distance less than the predetermined minimum distance toallow delivery of radiofrequency energy greater than the predeterminedthreshold energy to the electrode.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the disclosure can be more fully understood from thefollowing detailed description taken in conjunction with theaccompanying drawings, in which:

FIG. 1 is a block diagram illustrating one exemplary embodiment of arobotic surgical system;

FIG. 2 is a perspective view illustrating an exemplary embodiment of acontroller of the robotic surgical system of FIG. 1;

FIG. 3 depicts a perspective view illustrating an exemplary embodimentof a robotic arm cart of the robotic surgical system of FIG. 1;

FIG. 4 is a perspective view illustrating an exemplary embodiment of asurgical instrument suitable for use with the robotic surgical system ofFIG. 1;

FIG. 5 is a perspective view illustrating an underside of a baseassembly of the surgical instrument of FIG. 4;

FIG. 6 is a perspective view illustrating exemplary embodiments of anend effector and a shaft assembly articulation section of the surgicalinstrument of FIG. 4;

FIG. 7 is an exploded view the end effector and articulation section ofFIG. 6;

FIG. 8 is a lateral cross-sectional view of the end effector andarticulation section of FIG. 6;

FIG. 9 is a perspective view of the end effector and articulationsection of FIG. 6, omitting an outer sheath and clamp pad features forclarity;

FIG. 10 is a cross-sectional view of the end effector and articulationsection of FIG. 6, taken along line 10-10 of FIG. 8;

FIG. 11 is a cross-sectional view of the end effector and articulationsection of FIG. 6, taken along line 11-11 of FIG. 8;

FIG. 12 is a perspective view of a proximal end of the shaft assembly ofthe surgical instrument of FIG. 4;

FIG. 13 is an exploded view of the proximal end of the shaft assembly ofthe instrument of FIG. 4;

FIG. 14 is a perspective view of the proximal end of the instrument ofFIG. 4, with the outer cover omitted;

FIG. 15 is a top down view of the proximal end of the instrument of FIG.4, with the outer cover omitted;

FIG. 16 is an exploded view of the proximal end of the instrument ofFIG. 4, with the outer cover omitted;

FIG. 17 is a lateral cross-sectional view of a proximal portion of theproximal end of the instrument of FIG. 4, taken along line 17-17 of FIG.15;

FIG. 18 is a lateral cross-sectional view of a distal portion of theproximal end of the instrument of FIG. 4, taken along line 18-18 of FIG.15

FIG. 19 is a block diagram illustrating an exemplary embodiment of acontrol system suitable for use with the robotic surgical system of FIG.1;

FIG. 20A is a schematic illustration of a vessel such as an artery;

FIG. 20B is a schematic illustration of the vessel of FIG. 20A aftercompression by an end effector of a surgical instrument;

FIG. 20C is a schematic illustration of the vessel of FIG. 20B duringapplication of ultrasonic energy to cut the vessel;

FIG. 21 is a plot of exemplary embodiments of a treatment protocolimplemented by the control system of FIG. 19 that is suitable for usewith the end effector of FIG. 6 for inhibiting sticking of tissue to theultrasonic blade; (Part A) clamping forces applied to tissue by theclamping element as a function of time; (Part B) ultrasonic amplitudedelivered to the ultrasonic blade as a function of time;

FIG. 22 is a plot of another exemplary embodiment of control of the endeffector of FIG. 6 by the control system of FIG. 19 illustratingclamping forces (Part A) and ultrasonic energy amplitude delivered tothe ultrasonic blade (Part B) as a function of time;

FIG. 23 is a plot of another exemplary embodiment of control of the endeffector of FIG. 6 by the control system of FIG. 19 illustratingrelative ultrasonic energy amplitude that can be applied to anarticulating end effector as a function of articulation angle;

FIG. 24A is a side view of another exemplary embodiment of an endeffector including a clamping element, an ultrasonic blade, and one ormore radiofrequency (RF) electrodes;

FIG. 24B is another side view of the end effector of FIG. 24A;

FIG. 24C is a perspective sectional view of the end effector of FIGS.24A-24B;

FIG. 25 is a flow diagram illustrating an exemplary embodiment of amethod for fine control of closure of end effector of FIGS. 24A-24Cimplemented by the control system of FIG. 19;

FIG. 26 is a plot of an exemplary embodiment of motor torque as afunction of jaw member displacement according to the method of FIG. 25

FIG. 27 is a plot of another exemplary embodiment of control of the endeffector of FIGS. 24A-24C by the control system of FIG. 19 illustratingdisplacement of the clamping element (Part A) and clamping force appliedto a tissue (Part B) as a function of time;

FIG. 28 is a plot of an exemplary embodiment of clamping, feathering,cutting, and opening operations performed by the end effector of FIGS.24A-24C under control of the control system of FIG. 19; Amplitudes ofultrasonic and radiofrequency energy delivered to the end effector as afunction of time (Part A); Clamping forces applied to a tissue by thejaw member under load control as a function of time (Part B), Velocityof the jaw member under load control as a function of time (Part C);

FIG. 29 is a plot of an alternative embodiment of control of the endeffector of FIGS. 24A-24C by the control system of FIG. 19; Clampingforces applied to a tissue by the jaw member under load control as afunction of time (Part A), Velocity of the jaw member under load controlas a function of time (Part B); and

FIG. 30 is a plot of an alternative embodiment of control of the endeffector of FIGS. 24A-24C by the control system of FIG. 19; Clampingforces applied to a tissue by the jaw member under position control as afunction of time (Part A), Velocity of the jaw member under positioncontrol as a function of time (Part B).

DETAILED DESCRIPTION

Certain exemplary embodiments will now be described to provide anoverall understanding of the principles of the structure, function,manufacture, and use of the devices and methods disclosed herein. One ormore examples of these embodiments are illustrated in the accompanyingdrawings. Those skilled in the art will understand that the devices,systems, and methods specifically described herein and illustrated inthe accompanying drawings are non-limiting exemplary embodiments andthat the scope of the present invention is defined solely by the claims.The features illustrated or described in connection with one exemplaryembodiment can be combined with the features of other embodiments. Suchmodifications and variations are intended to be included within thescope of the present invention.

Further, in the present disclosure, like-named components of theembodiments generally have similar features, and thus within aparticular embodiment each feature of each like-named component is notnecessarily fully elaborated upon. Additionally, to the extent thatlinear or circular dimensions are used in the description of thedisclosed systems, devices, and methods, such dimensions are notintended to limit the types of shapes that can be used in conjunctionwith such systems, devices, and methods. A person skilled in the artwill recognize that an equivalent to such linear and circular dimensionscan easily be determined for any geometric shape. Sizes and shapes ofthe systems and devices, and the components thereof, can depend at leaston the anatomy of the subject in which the systems and devices will beused, the size and shape of components with which the systems anddevices will be used, and the methods and procedures in which thesystems and devices will be used.

It will be appreciated that the terms “proximal” and “distal” are usedherein with reference to a user, such as a clinician, gripping a handleof an instrument. Other spatial terms such as “front” and “rear”similarly correspond respectively to distal and proximal. It will befurther appreciated that for convenience and clarity, spatial terms suchas “vertical” and “horizontal” are used herein with respect to thedrawings. However, surgical instruments are used in many orientationsand positions, and these spatial terms are not intended to be limitingand absolute.

In general, embodiments of surgical systems are provided and can includeat least an electromechanical tool having an end effector and a controlsystem. The end effector can be designed for cutting tissue, e.g., asingle cutting blade or a pair of cutting blades, or for dissectingtissue. Depending on the design of the end effector, the surgical systemcan include one or more motors that actuate the electromechanical tooland/or one or more generators (e.g., ultrasound, radiofrequency, etc.)can be configured to deliver energy to tissue for treatment.

Embodiments of the control system can be configured to perform protocolsthat facilitate tissue treatments (e.g., clamping, cutting, cauterizing,etc.) by implementing limits and triggers on monitored parameters of anend effector engaging tissue. Examples of monitored parameters caninclude, but are not limited to, clamping forces applied to tissue,clamping velocity, clamping displacement, and energy supplied to endeffectors for tissue treatment. As discussed in greater detail below,these control protocols can compensate for reduced haptic feedback andensure that tissue treatments are performed properly.

Exemplary Robotic Surgical System Overview

FIG. 1 illustrates one exemplary embodiment of a robotic surgical system10. As shown, system 10 comprises at least one controller 14 and atleast one arm cart 18. The arm cart 18 can be mechanically and/orelectrically coupled to one or more robotic manipulators or arms 20.Each robotic arm 20 comprises one or more surgical instruments 22 forperforming various surgical tasks on a patient 24. Operation of arm cart18, including arms 20 and surgical instruments 22, can be directed by auser 12 (e.g., a clinician) from controller 14.

Optionally, embodiments of the system 10 can also include a secondcontroller 14′ that is configured for operation by a second user 12′.The second controller 14′ can direct operation of the arm cart 18 inconjunction with the first user 12′. For example, each of the users 12,12′ can control different arms 20 of the arm cart 18 or, in some cases,complete control of arm cart 18 can be passed between the users 12, 12′.In certain embodiments, additional arm carts (not shown) can be utilizedon the patient 24. These additional arm carts can be controlled by oneor more of the controllers (14, 14′).

Arm carts 18 and controllers 14, 14′ can be in communication with oneanother via a communications link 16, which can be any suitable type ofwired and/or wireless communications link carrying any suitable type ofsignal (e.g., electrical, optical, infrared, etc.) according to anysuitable communications protocol. Communications link 16 can be anactual physical link or it can be a logical link that uses one or moreactual physical links. When the link is a logical link the type ofphysical link can be a data link, uplink, downlink, fiber optic link,point-to-point link, for example.

FIG. 2 is a perspective view illustrating one exemplary embodiment of acontroller 30 that can serve as a controller 14 of system 10. In thisexample, controller 30 generally includes a user input assembly 32having precision user input features (not shown) that can be grasped bythe user and manipulated in space while the user views the surgicalprocedure via a display 34 (e.g., a stereo display). The display 34 canshow views from one or more endoscopes viewing the surgical site withinthe patient and/or any other suitable view(s). In addition, a feedbackmeter 36 can be viewed through the display 34 and provide the user witha visual indication of the amount of force being applied to a componentof the surgical instrument 22 (e.g., a cutting member or clampingmember, etc.).

The user input features of user input assembly 32 can also includemanual input devices that move with multiple degrees of freedom forintuitively actuating tools (e.g., for closing grasping saws, applyingan electrical potential to an electrode, etc.). As an example, manualinput devices can include actuatable handles and/or foot switches. Asshown in FIG. 2, the controller 30 can include one or more foot switches38 that are configured to provide additional control of arms 20 andsurgical instruments 22 to the user. Other sensor arrangements can beemployed to provide controller 30 with one or more indications regardingoperational conditions of the surgical instrument 22.

Embodiments of the controller 30 can also include a control system 39configured to control movement and actuation of one or more of theinstruments 22. For example, the control system 39 can include at leastone computer system that can include components (e.g. one or moreprocessors) that are configured for running one or more logic functionswith respect to a program stored in a memory coupled to the processor.For example, the processor can be coupled to the user input assembly 32and it can be configured for receiving sensed information, aggregatingit, and computing outputs based at least in part on the sensedinformation. These outputs can be transmitted to motors of theinstruments 22 to control the instruments 22 during use, as discussed ingreater detail below.

FIG. 3 is a perspective view illustrating one exemplary embodiment of arobotic arm cart 40 that can serve as the arm cart 18 of the system 10.In this example, the arm cart 40 can be configured to actuate aplurality of surgical instruments 50. While three instruments 50 areshown in this example, it should be understood that arm cart 40 can beoperable to support and actuate any suitable number of surgicalinstruments 50. Each of the surgical instruments 50 can be supported bya series of manually articulatable linkages, generally referred to asset-up joints 44, and a robotic manipulator 46. These structures areherein illustrated with protective covers extending over much of therobotic linkage. These protective covers can be optional, and they canbe limited in size or entirely eliminated in some versions to minimizethe inertia that can be encountered by the servo mechanisms used tomanipulate such devices, to limit the volume of moving components so asto avoid collisions, and to limit the overall weight of arm cart 40.

Each robotic manipulator 46 terminate at an instrument platform 70,which can be pivotable, rotatable, and otherwise movable by the roboticmanipulator 46. Each platform include an instrument dock 72 that isslidable along a pair of tracks 74 to further position instrument 50.Such sliding can be motorized in the present example. Each instrumentdock 72 can also include mechanical and electrical interfaces that canbe coupled with an interface assembly 52 of instrument 50. For example,the dock 72 can include four rotary outputs that couple withcomplementary rotary inputs of interface assembly 52. Such rotary drivefeatures can drive various functionalities in instrument 50, as isdescribed in various references cited herein and/or described in greaterdetail below. Electrical interfaces can establish communication viaphysical contact, inductive coupling, and/or otherwise; and can beoperable to provide electrical power to one or more features ininstrument 50, provide commands and/or data communication to instrument50, and/or provide commands and/or data communication from instrument50. Various suitable ways in which an instrument dock 72 canmechanically and electrically communicate with an interface assembly 52of an instrument 50 will be apparent to those of ordinary skill in theart in view of the teachings herein. It should also be understood thatinstrument 50 can include one or more cables that couple with a separatepower source and/or control unit, to provide communication of powerand/or commands/data to/from instrument 50.

The arm cart 40 can also include a base 48 that can be movable (e.g., bya single attendant to selectively position the arm cart 40 in relationto a patient). The arm cart 40 can generally have dimensions suitablefor transporting the arm cart 40 between operating rooms. The arm cart40 can be configured to fit through standard operating room doors andonto standard hospital elevators. In some versions, an automatedinstrument reloading system (not shown can also be positioned in or nearthe work envelope 60 of arm cart 40, to selectively reload components(e.g., staple cartridges, etc.) of instruments 50.

In addition to the foregoing, it can be understood that one or moreaspects of system 10 can be constructed in accordance with the teachingsfrom one or more of U.S. Pat. Nos. 5,792,135; 5,817,084; 5,878,193;6,231,565; 6,783,524; 6,364,888; 7,524,320; 7,691,098; 7,806,891;7,824,401; and/or U.S. Pub. No. 2013/0012957. The disclosures of each ofthe foregoing U.S. patents and U.S. patent publication are incorporatedby reference in their entirety. Still other suitable features andoperabilities that can be incorporated into system 10 will be apparentto those of ordinary skill in the art in view of the teachings herein.

While aspects of the disclosure are explained herein in the context of arobotic surgical system, it is understood that the present disclosure isapplicable to powered, non-robotic surgicval systems as well.

II. Ultrasonic Surgical Instrument with Articulation Feature

Ultrasonic surgical instruments are finding increasingly widespreadapplications in surgical procedures by virtue of the unique performancecharacteristics of such instruments. Depending upon specific instrumentconfigurations and operational parameters, ultrasonic surgicalinstruments can provide simultaneous or near-simultaneous cutting oftissue and hemostasis by coagulation, desirably minimizing patienttrauma. Ultrasonic surgical instruments of this nature can be configuredfor open surgical use, laparoscopic, or endoscopic surgical proceduresincluding robotic-assisted procedures.

FIGS. 4-18 are schematic diagrams illustrating an embodiment of anultrasonic surgical instrument 100 that can be used as at least oneinstrument 50 within system 10. At least part of instrument 100 can beconstructed and operable in accordance with the teachings of one or moreof U.S. Pat. Nos. 5,322,055; 5,873,873; 5,980,510; 6,325,811; 6,783,524;8,461,744, 9,023,071, 9,095,367, 9,393,037, U.S. Pub. No. 2006/0079874;U.S. Pub. No. 2007/0191713; U.S. Pub. No. 2007/0282333; U.S. Pub. No.2008/0200940; and/or U.S. Pat. App. No. 61/410,603. Each of theforegoing patents, publications, and applications are incorporated byreference in their entirety. As described therein and in greater detailbelow, the instrument 100 can be configured to cut tissue, coagulatetissue, and to seal or weld tissue (e.g., blood vessels) substantiallysimultaneously. In other words, the instrument 100 operates similar toan endocutter type of stapler, except that the instrument 100 providestissue welding through application of ultrasonic vibrational energyinstead of providing lines of staples to join tissue.

Ultrasonic vibrational energy can separate tissue similar to severing oftissue by a translating blade positioned at the distal end of thesurgical instrument. Vibrating at high frequencies (e.g., about 55,500times per second), the ultrasonic blade can denature proteins in thetissue to form a sticky coagulum. Pressure exerted on tissue by theblade surface can collapse blood vessels and allow the coagulum to forma hemostatic seal. The precision of cutting and coagulation can becontrolled by the surgeon's technique and adjusting one or more of theamplitude of the ultrasonic vibrations, the blade edge, tissue traction,and ultrasonic blade pressure.

As an example, the instrument 100 can have various structural andfunctional similarities with the HARMONIC ACE® Ultrasonic Shears, theHARMONIC WAVE® Ultrasonic Shears, the HARMONIC FOCUS® Ultrasonic Shears,and/or the HARMONIC SYNERGY® Ultrasonic Blades. Furthermore, theinstrument 100 can have various structural and functional similaritieswith the devices taught in any of the other references that are citedand incorporated by reference herein.

As shown in FIG. 4, the instrument 100 includes an interface assembly200, a shaft assembly 110, an articulation section 130, and an endeffector 150. The interface assembly 200 can be configured to couplewith the instrument dock 72 of the robotic arm cart 40 and it can beconfigured to drive the articulation section 130 and the end effector150 as described in greater detail below. As also described in greaterdetail below, the instrument 100 can be configured to articulate endeffector 150 to provide a desired positioning relative to tissue (e.g.,a large blood vessel, etc.), then apply ultrasonic vibrational energyand/or RF energy to the tissue with end effector 150 to thereby cut,coagulate, and seal the tissue.

The instrument 100 includes an ultrasonic transducer 120, which can beoperable to convert electrical power into ultrasonic vibrations. In someinstances, the ultrasonic transducer 120 can receive power directlythrough dock 72. In some other instances, the transducer 120 can includea cable 302 that directly couples the ultrasonic transducer 120 with agenerator 300. The generator 300 can include a power source and controlmodule that can be configured to provide a power profile to transducer120 that is suitable for the generation of ultrasonic vibrations throughtransducer 120. Optionally, the generator 300 can also be suitable forgeneration of RF signals.

In an embodiment, the generator 300 can include a GEN 300 sold byEthicon Endo-Surgery, Inc. of Cincinnati, Ohio. In addition or in thealternative, the generator 300 can be constructed in accordance with atleast some of the teachings of U.S. Pat. No. 8,986,302, entitled“Surgical Generator for Ultrasonic and Electrosurgical Devices,”published Apr. 14, 2011, which is incorporated by reference in itsentirety. Still other suitable forms that generator 300 can take, aswell as various features and operabilities that generator 300 canprovide, will be apparent to those of ordinary skill in the art in viewof the teachings herein.

In an embodiment, at least part of the functionality of generator 300can be incorporated directly into the interface assembly 200. As anexample, the interface assembly 200 can include an integral battery orother integral power source, as well as any circuitry needed tocondition power from a battery or other integral power source to driveultrasonic transducer 120.

A. End Effector and Acoustic Drivetrain

As illustrated in FIGS. 6-8, the end effector 150 can include a clamparm 152 and an ultrasonic blade 160. The clamp arm 152 includes a clamppad 154 that is secured to the underside of clamp arm 152, facing theultrasonic blade 160. The clamp arm 152 can be pivotally secured to adistally projecting tongue 133 (FIGS. 7-8) of a first ribbed bodyportion 132. The first ribbed body portion 132 can form part of thearticulation section 130, as described in greater detail below. Theclamp arm 152 is operable to selectively pivot toward and away from theultrasonic blade 160 to selectively clamp tissue between the clamp arm152 and the ultrasonic blade 160. A pair of arms 156 extend transverselyto clamp arm 152 and are secured to a pin 170 that extends laterallybetween arms 156. A rod 174 is secured to pin 170. Rod 174 extendsdistally from a closure tube 176 and is unitarily secured to closuretube 176.

A driving ring 178 can be secured to the proximal end of closure tube176. In particular, and as illustrated in FIG. 13, the proximal end ofclosure tube 176 can include a transverse opening 177 that can beconfigured to align with a transverse opening 179 of the driving ring178. The openings 177, 179 are configured to receive a set screw (notshown) or other feature that can secure the driving ring 178 to theclosure tube 176. The driving ring 178 is slidably and coaxiallydisposed about the exterior of the outer sheath 112; while the closuretube 176 is slidably and coaxially disposed within the interior of theouter sheath 112. However, the outer sheath 112 can include alongitudinally extending slot 114 that can be configured to receive theset screw and it can secure the driving ring 178 to the closure tube176. Thus, the slot 114 can allow the driving ring 178 and the closuretube 176 to translate together relative to the outer sheath 112. Thepositioning of the set screw in the slot 114 can also provide rotationof the closure tube 176 and the driving ring 178 about the longitudinalaxis of outer sheath 112 when the outer sheath 112 is rotated about itslongitudinal axis, as described in greater detail below.

As also described in greater detail below, the interface assembly 200can include features that are operable to drive the driving ring 178,the closure tube 176, and the rod 174 longitudinally relative to theouter sheath 112 and relative to the articulation section 130. It can beunderstood that this translation of the driving ring 178, the closuretube 176, and the rod 174 can provide pivoting of the clamp arm 152toward the ultrasonic blade 160 when the ring 178, the tube 176, and therod 174 are translated proximally; or away from the ultrasonic blade 160when the ring 178, the tube 176, and the rod 174 are translateddistally. The rod 174 can be sufficiently flexible to bend with thearticulation section 130. However, the rod 174 can have sufficienttensile and compressive strength to drive the clamp arm 152 when the rod174 is translated, regardless of whether the articulation section 130 isin a straight or bent configuration.

As illustrated in FIGS. 7-8 a leaf spring 172 is captured between theclamp arm 152 and the clamp pad 154 and it abuts the distal face oftongue 133. The leaf spring 172 can be resiliently biased to drive theclamp arm 152 away from the ultrasonic blade 160 to the open position,shown in FIGS. 4, 6, and 8. The leaf spring 172 can therefore furtherbias the tube 176 and the rod 174 distally. Of course, like othercomponents described herein, the leaf spring 172 can be omitted ifdesired. Furthermore, the clamp arm 152 and the clamp pad 154 can beomitted if desired.

Embodiments of the ultrasonic blade 160 can be configured to vibrate atultrasonic frequencies in order to effectively cut through and sealtissue, particularly when the tissue is being clamped between the clamppad 154 and the ultrasonic blade 160. The ultrasonic blade 160 can bepositioned at the distal end of an acoustic drivetrain.

This acoustic drivetrain includes the ultrasonic transducer 120, a rigidacoustic waveguide 180, and a flexible acoustic waveguide 166. As bestseen in FIGS. 5 and 12-17, ultrasonic transducer 120 includes a set ofpiezoelectric discs 122 located proximal to a horn 182 of rigid acousticwaveguide 180. Piezoelectric discs 122 are coaxially positioned along aproximally extending bolt 181, which is a unitary feature of acousticwaveguide 180 located proximal to horn 182. An endmass nut 124 issecured to bolt 181, thereby securing piezoelectric discs 122 to rigidacoustic waveguide 180. As noted above, piezoelectric discs 122 areoperable to convert electrical power into ultrasonic vibrations, whichare then transmitted along rigid acoustic waveguide 180 to theultrasonic blade 160. The rigid acoustic waveguide 180 is illustrated inFIGS. 13 and 17-18. As shown in FIG. 13, rigid acoustic waveguide 180includes a transverse opening 186 that complements a transverse opening118 formed in outer sheath 112. A pin 184 is disposed in openings 118,186 to couple outer sheath 112 with rigid acoustic waveguide 180. Thiscoupling provides rotation of acoustic waveguide 180 and the rest of theacoustic drivetrain about the longitudinal axis of outer sheath 112 whenouter sheath 112 is rotated about its longitudinal axis as will bedescribed in greater detail below. As an example, the opening 186 can belocated at a position corresponding to a node associated with resonantultrasonic vibrations communicated through rigid acoustic waveguide 180.

The rigid acoustic waveguide 180 distally terminate in a coupling 188,which can be seen in FIGS. 8-11 and 13. The coupling 188 is secured tothe coupling 168 by a double-threaded bolt 169. The coupling 168 islocated at the proximal end of the flexible acoustic waveguide 166. Asillustrated in FIGS. 7-11, the flexible acoustic waveguide 166 includesa distal flange 136, a proximal flange 138, and a narrowed section 164located between flanges 138. As an example, the flanges 136, 138 can belocated at positions corresponding to nodes associated with resonantultrasonic vibrations communicated through the flexible acousticwaveguide 166. The narrowed section 164 can be configured to allowflexible acoustic waveguide 166 to flex without significantly affectingthe ability of flexible acoustic waveguide 166 to transmit ultrasonicvibrations. The narrowed section 164 can be configured in accordancewith one or more teachings of U.S. patent application Ser. No.13/538,588 and/or U.S. patent application Ser. No. 13/657,553, each ofwhich are incorporated by reference in their entirety. Either of thewaveguides 166, 180 can be configured to amplify mechanical vibrationstransmitted through the waveguides 166, 180. Furthermore, either of thewaveguides 166, 180 can include features operable to control the gain ofthe longitudinal vibrations along the waveguides 166, 180 and/orfeatures to tune the waveguides 166, 180 to the resonant frequency ofthe system.

The distal end of the ultrasonic blade 160 can be located at a positioncorresponding to an anti-node associated with resonant ultrasonicvibrations communicated through the flexible acoustic waveguide 166, inorder to tune the acoustic assembly to a preferred resonant frequencyf_(o) when the acoustic assembly is not loaded by tissue. When theultrasonic transducer 120 is energized, the distal end of the ultrasonicblade 160 can be configured to move longitudinally in the range from,for example, approximately 10 to 500 microns peak-to-peak, and in someinstances in the range from about 20 microns to about 200 microns at apredetermined vibratory frequency f_(o) (e.g., about 55.5 kHz). When theultrasonic transducer 120 is activated, these mechanical oscillationsare transmitted through the waveguides 180, 166 to reach the ultrasonicblade 160, thereby providing oscillation of the ultrasonic blade 160 atthe resonant ultrasonic frequency. Thus, when tissue is secured betweenthe ultrasonic blade 160 and the clamp pad 154, the ultrasonicoscillation of the ultrasonic blade 160 can simultaneously sever thetissue and denature the proteins in adjacent tissue cells, therebyproviding a coagulative effect with relatively little thermal spread. Insome versions, an electrical current can also be provided through theultrasonic blade 160 and the clamp arm 152 to also cauterize the tissue.

While some configurations for an acoustic transmission assembly andultrasonic transducer 120 have been described, still other suitableconfigurations for an acoustic transmission assembly and the ultrasonictransducer 120 will be apparent to one or ordinary skill in the art inview of the teachings herein. Similarly, other suitable configurationsfor the end effector 150 will be apparent to those of ordinary skill inthe art in view of the teachings herein.

B. Exemplary Shaft Assembly and Articulation Section

The shaft assembly 110 can extend distally from the interface assembly200. The articulation section 130 can be located at the distal end ofthe shaft assembly 110, with the end effector 150 being located distalto articulation section 130. The shaft assembly 110 can include an outersheath 112 that encloses drive features and the above-described acoustictransmission features that couple the interface assembly 200 with thearticulation section 130 and the end effector 150. The shaft assembly110 can be rotatable about the longitudinal axis defined by the outersheath 112, relative to interface assembly 200. Such rotation canprovide rotation of the end effector 150, the articulation section 130,and the shaft assembly 110 unitarily. Of course, rotatable features cansimply be omitted if desired.

The articulation section 130 is operable to selectively position the endeffector 150 at various lateral deflection angles relative to thelongitudinal axis defined by the outer sheath 112. The articulationsection 130 can take a variety of forms. As an example, the articulationsection 130 can be configured in accordance with one or more teachingsof U.S. Patent Publication. No. 2012/0078247, the entirety of which isincorporated by reference. Alternatively or additionally, thearticulation section 130 can be configured in accordance with one ormore teachings of U.S. patent application Ser. No. 13/538,588 and/orU.S. patent application Ser. No. 13/657,553, each of which areincorporated by reference in their entirety. Various other suitableforms that the articulation section 130 can take will be apparent tothose of ordinary skill in the art in view of the teachings herein. Itshould also be understood that some versions of instrument 100 can omitthe articulation section 130.

As illustrated in FIGS. 6-11, the articulation section 130 can includethe first ribbed body portion 132 and a second ribbed body portion 134,with a pair of articulation bands 140, 142 extending through channelsdefined at the interfaces between the ribbed body portions 132, 134. Theribbed body portions 132, 134 can be substantially longitudinallypositioned between the flanges 136, 138 of the flexible acousticwaveguide 166. The distal ends of the articulation bands 140, 142 can beunitarily secured to distal flange 136. The articulation bands 140, 142can also pass through the proximal flange 138, yet articulation bands140, 142 can be slidable relative to the proximal flange 138.

The proximal end of the articulation band 140 can be secured to a firstdrive ring 250; while the proximal end of articulation band 142 can besecured to a second drive ring 251. As illustrated in FIGS. 13 and 17,the first drive ring 250 includes an annular flange 252 and an inwardlyprojecting anchor feature 254; while the second drive ring 251 alsoincludes an annular flange 253 and an inwardly projecting anchor feature255. The proximal end of articulation band 140 can be fixedly securedwithin the anchor feature 254 while the proximal end of articulationband 142 can be fixedly secured within the anchor feature 255. The driverings 250, 251 can be slidably disposed about the proximal end of outersheath 112. The outer sheath 112 can include a pair of longitudinallyextending slots 116, 117 that are configured to respectively receive theanchor features 254, 255. The slots 116, 117 can allow the drive rings250, 251 to translate relative to outer sheath 112. The positioning ofthe anchor features 254, 255 in the slots 116, 117 can also providerotation of the rings 250, 251 and the articulation bands 140, 142 aboutthe longitudinal axis of the outer sheath 112 when the outer sheath 112is rotated about its longitudinal axis as described in greater detailbelow.

As described in greater detail below, the interface assembly 200 isoperable to selectively pull one of the articulation bands 140, 142proximally by pulling proximally on the drive ring 250; whilesimultaneously allowing the other one of the articulation bands 140, 142and the drive ring 251 to translate distally. It should be understoodthat, as one of the articulation bands 140, 142 is pulled proximally,this will cause articulation section 130 to bend, thereby laterallydeflecting the end effector 150 away from the longitudinal axis of theshaft assembly 110 at an articulation angle. In particular, the endeffector 150 will be articulated toward the one of the articulationbands 140, 142 that is being pulled proximally. During sucharticulation, the other of the articulation bands 140, 142 will bepulled distally by the flange 136. The ribbed body portions 132, 134 andthe narrowed section 164 can all be sufficiently flexible to accommodatethe above-described articulation of the end effector 150.

C. Exemplary Robotic Arm Interface Assembly

The interface assembly 200 is illustrated in greater detail in FIGS. 5and 14-18. As shown, the interface assembly 200 comprises a base 202 anda housing 204. For clarity, the housing 204 is only shown in FIG. 4 andis omitted from FIGS. 5 and 14-18. The housing 204 can include a shellthat encloses drive components. In certain embodiments, the housing 204can also include an electronic circuit board, chip, and/or otherfeatures that can be configured to identify the instrument 100.

The base 202 is configured to engage the dock 72 of the robotic arm cart40. While not shown, it should be understood that the base 202 can alsoinclude one or more electrical contacts and/or other features operableto establish electrical communication with a complementary features ofthe dock 72. A shaft support structure 206 extends upwardly from thebase 202 and it can provide support to the shaft assembly 110 whilestill allowing the shaft assembly 110 to rotate. By way of example only,the shaft support structure 206 can include a busing, bearings, and/orother features that facilitate rotation of the shaft assembly 110relative to the support structure 206.

As shown in FIG. 5, the base 202 further include three drive discs 220,240, 260 that are rotatable relative to the base 202. Each of the discs220, 240, 260 includes a respective pair of unitary pins 222, 242, 262that couple with complementary recesses not shown in drive elements ofdock 72. In certain embodiments, one pin 222, 242, 262 of each pair canbe closer to the axis of rotation of the corresponding disc 220, 240,260 to ensure proper angular orientation of discs 220, 240, 260 relativeto the corresponding drive element of the dock 72.

As illustrated in FIGS. 14-16, a drive shaft 224, 244, 264 extendsunitarily upwardly from each of the discs 220, 240, 260. As described ingreater detail below, the discs 220, 240, 260 can be independentlyoperable to provide independent rotation of the shaft assembly 110,bending of the articulation section 130, and translation of the closuretube 176, through independent rotation of the drive shafts 224, 244,264. The base 202 can also include an idle disc 280, which does notrotate or drive any components. A pair of fixed pivot pins 282, 284 canextend unitarily upwardly from disc 280.

As illustrated in FIGS. 14-16, a first helical gear 226 can be fixedlysecured to drive shaft 224, such that rotation of the corresponding disc220 provides rotation of the first helical gear 226. The first helicalgear 226 meshes with a second helical gear 230, which is unitarilysecured to a sleeve 232. The sleeve 232 is unitarily secured to theouter sheath 112. Thus, rotation of the first helical gear 226 providesrotation of the shaft assembly 110. Rotation of the first helical gear226 about a first axis isconverted into rotation of second helical gear230 about a second axis, which can be orthogonal to the first axis. Aclockwise (CW) rotation of the second helical gear 230 (viewed from thetop down) can result in CW rotation of the shaft assembly 110 (viewedfrom the distal end of shaft assembly 110) toward the proximal end ofthe shaft assembly 110, depending on the thread orientation of helicalgears 226, 230. A counter-clockwise (CCW) rotation of second helicalgear 132 (viewed from the top down) results in CCW rotation of the shaftassembly 110 (viewed from the distal end of shaft assembly 110) towardthe proximal end of the shaft assembly 110, again depending on thethread orientation of helical gears 226, 230. It should therefore beunderstood that shaft assembly 110 can be actuated by rotating driveshaft 224. Other suitable ways in which the shaft assembly 110 can berotated will be apparent to those of ordinary skill in the art in viewof the teachings herein.

As illustrated in FIGS. 14-16, a pair of cylindraceous cams 246, 248 arefixedly secured to the drive shaft 244, such that rotation of thecorresponding disc 240 provides rotation of the cams 246, 248. The cams246, 248 can each be mounted eccentrically to the drive shaft 244, suchthat the longitudinal axes of the cams 246, 248 are offset from, yetparallel to, the longitudinal axis of the drive shaft 244. In addition,the cams 246, 248 can be offset in an opposing manner, such that thecams 246, 248 laterally protrude relative to the drive shaft 244 inopposite directions. The cams 246, 248 can be positioned to drive thepivot arms 286, 288. The pivot arm 286 can be pivotally coupled with thepivot pin 282; while the pivot arm 288 can be pivotally coupled with thepivot pin 284. The first drive ring 250 can pass through an opening 287formed through the first drive arm 286; while the second drive ring 251can pass through an opening 289 formed through the second drive arm 288.Flanges 252, 253 can each have an outer diameter that can be larger thanthe inner diameter of the corresponding opening 287, 289. The flanges252, 253 can thus restrict distal movement of the rings 250, 251relative to respective drive arms 286, 288.

As the drive shaft 244 is rotated, one of the cams 246, 248 will pushproximally on the corresponding arm 286, 288, depending on thepositioning of these components and the angular position of vcams 246,248 at the time of rotation. In some instances, vcam 246 can drive thearm 288 proximally, such that the arm 288 pivots CCW (viewed from thetop down) about the pin 284. The arm 288 will bear against the flange253 during such pivoting, thereby pulling the ring 251 and thearticulation band 142 proximally. This proximal movement of thearticulation band 142 will cause the articulation section 130 to bend,with the end effector 150 being deflected toward the band 142. Thisbending of the articulation section 130 will pull the articulation band140 distally, which will in turn pull the ring 250 and its flange 252distally. The distal motion of flange 252 will drive arm 286 distally,such that arm 286 pivots CW (viewed from the top down) about the pin282. The cam 248 can be oriented to permit such distal pivoting of thearm 286. As the drive shaft 244 continues to rotate, or if drive shaft244 is rotated in the opposite direction, the above pushing and pullingwill eventually be reversed. In other words, the cam 248 can drive thearm 286 proximally while the cam 246 can permit the arm 288 to pivotdistally during bending of the articulation section 130 to providedeflection of the end effector 150 toward the band 140. It shouldtherefore be understood that articulation section 130 may be actuated byrotating drive shaft 244. Other suitable ways in which the articulationsection 130 can be actuated will be apparent to those of ordinary skillin the art in view of the teachings herein.

As illustrated in FIGS. 14-16, a cylindraceous cam 266 can be fixedlysecured to the drive shaft 264, such that rotation of the correspondingdisc 260 can provide rotation of the cam 266. The cam 266 can be mountedeccentrically to the drive shaft 264, such that the longitudinal axis ofthe cam 266 can be offset from yet parallel to the longitudinal axis ofthe drive shaft 264. the cam 266 can be disposed in an oblong opening272 formed through a rack 270, which can be translatable relative to thebase 202. The rack 270 includes a laterally extending fork 274. The fork274 can be disposed in an annular recess 278 of the driving ring 178,which can be secured to the closure tube 176 as noted above. Theconfiguration of the cam 266 and the configuration of the opening 272can provide a relationship whereby the rack 270 translateslongitudinally in response to rotation of the drive shaft 264 and thecam 266. This translation of the rack 270 can provide translation of theclosure tube 176 due to the engagement between the fork 274 and thedriving ring 178; and the engagement between the driving ring 178 andthe closure tube 176. The clamp arm 152 can be selectively driven awayfrom or toward the ultrasonic blade 160 by rotating the drive shaft 264.Other suitable ways in which the clamp arm 152 can be actuated will beapparent to those of ordinary skill in the art in view of the teachingsherein.

D. Exemplary Operation

In use, the arm cart 40 can be used to insert the end effector 150 intoa patient via a trocar. The articulation section 130 can besubstantially straight, and the clamp arm 152 can be pivoted toward theultrasonic blade 160, when the end effector 150 and part of the shaftassembly 110 are inserted through the trocar. The drive shaft 224 can berotated through drive features in the dock 72 that are coupled with thecorresponding disc 220, to position the end effector 150 at a desiredangular orientation relative to the tissue. The drive shaft 244 can thenbe rotated through drive features in the dock 72 that are coupled withthe corresponding disc 240, to pivot or flex the articulation section130 of the shaft assembly 110 in order to position the end effector 150at a desired position and orientation relative to an anatomicalstructure within the patient. The drive shaft 264 can then be rotatedthrough drive features in the dock 72 that are coupled with thecorresponding disc 260, to pivot the clamp arm 152 away from theultrasonic blade 160, thereby effectively opening the end effector 150.

Tissue of the anatomical structure can be then captured between theclamp pad 154 and the ultrasonic blade 160 by rotating the drive shaft264 to advance the closure tube 176 distally, by actuating drivefeatures in the dock 72 that are coupled with the corresponding disc260. In some instances, this can involves clamping two layers of tissueforming part of a natural lumen defining anatomical structure (e.g., ablood vessel, portion of gastrointestinal tract, portion of reproductivesystem, etc.) in a patient. However, it should be understood thatembodiments of the instrument 100 can be used on various kinds oftissues and anatomical locations. With tissue captured between the clamppad 154 and the ultrasonic blade 160, the ultrasonic transducer 120 canbe activated to provide ultrasonic vibrations to the ultrasonic blade160. This can simultaneously sever the tissue and denature proteins inadjacent tissue cells, thereby providing a coagulative effect withrelatively little thermal spread.

The above operation of the shaft assembly 110, the articulation section130, and the end effector 150 can be repeated as many times as desiredin various locations within the patient. When the operator wishes towithdraw the end effector 150 from the patient, the drive shaft 244 canbe rotated through drive features in the dock 72 that are coupled withthe corresponding disc 240, to straighten the articulation section 130.The drive shaft 264 can be rotated through drive features in the dock 72that are coupled with the corresponding disc 260, to pivot the clamp arm152 toward the ultrasonic blade 160, thereby effectively closing the endeffector 150. The arm cart 40 can be then used to withdraw the endeffector 150 from the patient and trocar. Other suitable ways in whichinstrument 100 can be operable and operated will be apparent to those ofordinary skill in the art in view of the teachings herein.

III. Treatment Protocols for Cutting, Coagulating, and Sealing Tissue

A. Control System

The control system 39 can be configured to implement one or moretreatment protocols for cutting, coagulating, and sealing tissue. Asdiscussed in detail below, the control system 39 can be implementedusing one or more computer systems, which may also be referred to hereinas digital data processing systems and programmable systems.

One or more aspects or features of the control system 39 can be realizedin digital electronic circuitry, integrated circuitry, speciallydesigned application specific integrated circuits (ASICs), fieldprogrammable gate arrays (FPGAs) computer hardware, firmware, software,and/or combinations thereof. These various aspects or features caninclude implementation in one or more computer programs that areexecutable and/or interpretable on a programmable system including atleast one programmable processor, which can be special or generalpurpose, coupled to receive data and instructions from, and to transmitdata and instructions to, a storage system, at least one input device,and at least one output device. The programmable system or computersystem may include clients and servers. A client and server aregenerally remote from each other and typically interact through acommunication network. The relationship of client and server arises byvirtue of computer programs running on the respective computers andhaving a client-server relationship to each other.

The computer programs, which can also be referred to as programs,software, software applications, applications, components, or code,include machine instructions for a programmable processor, and can beimplemented in a high-level procedural language, an object-orientedprogramming language, a functional programming language, a logicalprogramming language, and/or in assembly/machine language. As usedherein, the term “machine-readable medium” refers to any computerprogram product, apparatus and/or device, such as for example magneticdiscs, optical disks, memory, and Programmable Logic Devices (PLDs),used to provide machine instructions and/or data to a programmableprocessor, including a machine-readable medium that receives machineinstructions as a machine-readable signal. The term “machine-readablesignal” refers to any signal used to provide machine instructions and/ordata to a programmable processor. The machine-readable medium can storesuch machine instructions non-transitorily, such as for example as woulda non-transient solid-state memory or a magnetic hard drive or anyequivalent storage medium. The machine-readable medium can alternativelyor additionally store such machine instructions in a transient manner,such as for example as would a processor cache or other random accessmemory associated with one or more physical processor cores.

To provide for interaction with the user, one or more aspects orfeatures of the subject matter described herein can be implemented on acomputer having a display device, such as for example a cathode ray tube(CRT) or a liquid crystal display (LCD) or a light emitting diode (LED)monitor for displaying information to the user and a keyboard and apointing device, e.g., a mouse, a trackball, etc., by which the user mayprovide input to the computer. Other kinds of devices can be used toprovide for interaction with a user as well. For example, feedbackprovided to the user can be any form of sensory feedback, such as forexample visual feedback, auditory feedback, or tactile feedback; andinput from the user may be received in any form, including, but notlimited to, acoustic, speech, or tactile input. Other possible inputdevices include, but are not limited to, touch screens or othertouch-sensitive devices such as single or multi-point resistive orcapacitive trackpads, voice recognition hardware and software, opticalscanners, optical pointers, digital image capture devices and associatedinterpretation software, and the like.

An exemplary embodiment of the control system 39 is illustrated FIG. 19as computer system 1900. As shown, the computer system 1900 includes oneor more processors 1902 which can control the operation of the computersystem 1900. “Processors” are also referred to herein as “controllers.”The processor(s) 1902 can include any type of microprocessor or centralprocessing unit (CPU), including programmable general-purpose orspecial-purpose microprocessors and/or any one of a variety ofproprietary or commercially available single or multi-processor systems.The computer system 1900 can also include one or more memories 1904,which can provide temporary storage for code to be executed by theprocessor(s) 1902 or for data acquired from one or more users, storagedevices, and/or databases. The memory 1904 can include read-only memory(ROM), flash memory, one or more varieties of random access memory (RAM)(e.g., static RAM (SRAM), dynamic RAM (DRAM), or synchronous DRAM(SDRAM)), and/or a combination of memory technologies.

The various elements of the computer system 600 can be coupled to a bussystem 1912. The illustrated bus system 1912 is an abstraction thatrepresents any one or more separate physical busses, communicationlines/interfaces, and/or multi-drop or point-to-point connections,connected by appropriate bridges, adapters, and/or controllers. Thecomputer system 600 can also include one or more network interface(s)1906, one or more input/output (TO) interface(s) 1908 that can includeone or more interface components, and one or more storage device(s)1910.

The network interface(s) 1906 can enable the computer system 1900 tocommunicate with remote devices, e.g., motors coupled to the drivesystem drive discs 220, 240, 260 and/or the generator 300. Suchcommunication can occur over dedicated transmission lines, over anetwork, and the like. As an example, a network can be any combinationof remote connection interfaces, Ethernet adapters, and/or other localarea network (LAN) adapters. The IO interface(s) 1908 can include one ormore interface components to connect the computer system 1900 with otherelectronic equipment, such as the sensors located on the motor(s). Fornon-limiting example, the IO interface(s) 1908 can include high speeddata ports, such as universal serial bus (USB) ports, 1394 ports, Wi-Fi,Bluetooth, etc. Additionally, the computer system 1900 can be accessibleto a human user, and thus the IO interface(s) 1908 can include displays,speakers, keyboards, pointing devices, and/or various other video,audio, or alphanumeric interfaces. The storage device(s) 1910 caninclude any conventional medium for storing data in a non-volatileand/or non-transient manner. The storage device(s) 1910 can thus holddata and/or instructions in a persistent state, i.e., the value(s) areretained despite interruption of power to the computer system 1900. Thestorage device(s) 1910 can include one or more hard disk drives, flashdrives, USB drives, optical drives, various media cards, diskettes,compact discs, and/or any combination thereof and can be directlyconnected to the computer system 1900 or remotely connected thereto,such as over a network. In an exemplary embodiment, the storagedevice(s) 1910 can include a tangible or non-transitory computerreadable medium configured to store data, e.g., a hard disk drive, aflash drive, a USB drive, an optical drive, a media card, a diskette, acompact disc, etc.

The elements illustrated in FIG. 19 can be some or all of the elementsof a single physical machine. In addition, not all of the illustratedelements need to be located on or in the same physical machine.Exemplary computer systems include conventional desktop computers,workstations, minicomputers, laptop computers, tablet computers,personal digital assistants (PDAs), mobile phones, and the like.

The computer system 1900 can include a web browser for retrieving webpages or other markup language streams, presenting those pages and/orstreams (visually, aurally, or otherwise), executing scripts, controlsand other code on those pages/streams, accepting user input with respectto those pages/streams (e.g., for purposes of completing input fields),issuing HyperText Transfer Protocol (HTTP) requests with respect tothose pages/streams or otherwise (e.g., for submitting to a serverinformation from the completed input fields), and so forth. The webpages or other markup language can be in HyperText Markup Language(HTML) or other conventional forms, including embedded Extensible MarkupLanguage (XML), scripts, controls, and so forth. The computer system1900 can also include a web server for generating and/or delivering theweb pages to client computer systems.

In an exemplary embodiment, the computer system 1900 can be provided asa single unit, e.g., as a single server, as a single tower, containedwithin a single housing, etc. The single unit can be modular such thatvarious aspects thereof can be swapped in and out as needed for, e.g.,upgrade, replacement, maintenance, etc., without interruptingfunctionality of any other aspects of the system. The single unit canthus also be scalable with the ability to be added to as additionalmodules and/or additional functionality of existing modules are desiredand/or improved upon.

A computer system can also include any of a variety of other softwareand/or hardware components, including by way of non-limiting example,operating systems and database management systems. Although an exemplarycomputer system is depicted and described herein, it will be appreciatedthat this is for sake of generality and convenience. In otherembodiments, the computer system may differ in architecture andoperation from that shown and described here.

B. Tissue Treatments Using Ultrasonic Surgical Instruments

As noted above, cutting, coagulation, and sealing of tissue usingultrasonic surgical instruments can be accomplished by a combination ofpressure from an ultrasonic blade and ultrasonic vibrations of theultrasonic blade. This process is schematically illustrated in FIGS.20A-20C. FIG. 20A shows a blood vessel 2000 in cross-section beforecontact with an ultrasonic surgical instrument. As shown, the bloodvessel 2000 can include an outer layer or adventita 2002, a middle layeror media 2004, and an inner layer or intima 2006. When a sufficientcompressive or clamping force F_(c) is applied to the blood vessel 2000,the middle layer 2004 can break apart, leaving only the outer layer 2002and inner layer 2006 intact. Subsequently, while maintaining theclamping force F_(c), ultrasonic energy can be applied to an ultrasonicblade of the ultrasonic surgical instrument, as further shown in FIG.20C. Vibration of the ultrasonic blade can transfer mechanical energy tothe blood vessel 2000, breaking hydrogen bonds and producing heat byfriction. This frictional heat can denature proteins within the bloodvessel 2000, forming a coagulum 2010 that can seal the blood vessel2000. Once the blood vessel 2000 is sealed, vibration of the ultrasonicblade and can also be employed to cut the blood vessel 2000.

a. Tissue Treatment Protocols Inhibiting Tissue Sticking

In general, as discussed above, the end effector 150 can be configuredto clamp, cut, and coagulate tissue. As an example, the end effector 150can be configured to receive tissue between the clamp arm 152 and theultrasonic blade 160, where the distance separating the clamp arm 152from the ultrasonic blade 160 in an open position can be dimensioned toreceive tissue of predetermined thickness. Movement of the clamp arm 152towards the ultrasonic blade 160 can apply a clamping force to tissuedisposed between the clamp arm 152 and the ultrasonic blade 160, whiletransmission of ultrasonic energy to the ultrasonic blade 160 (e.g.,mechanical vibrations at ultrasonic frequencies) can coagulate and cutthe tissue.

One problem encountered during the use of ultrasonic surgicalinstruments for cutting tissue is sticking of tissue to the ultrasonicblade. When sticking occurs, removal of the ultrasonic blade can causetissue tearing and additional bleeding. Accordingly, embodiments of thecontrol system 39 can be configured to provide treatment protocols thatreduce or eliminate the likelihood of tissue sticking to ultrasonicblades. As discussed in greater detail below, the clamping force can bevaried between predetermined levels before or during transmission ofultrasonic energy to the ultrasonic blade 160 to inhibit tissue stickingto the ultrasonic blade 160.

FIG. 21 illustrates one exemplary embodiment of a tissue treatmentprotocol for clamping, coagulating, and cutting tissue with anultrasonic surgical instrument (e.g., surgical instrument 100) that caninhibit tissue sticking to the ultrasonic surgical instrument 100. PartA of FIG. 21 presents clamping forces applied to tissue by the clamp arm152 as a function of time. Part B of FIG. 21 presents correspondingamplitudes of ultrasonic vibrations delivered to the ultrasonic blade160 as a function of time. As discussed below, the control system 39 canimplement the treatment protocol such that a clamping force applied totissue can be varied before transmission of ultrasonic vibrations to theultrasonic blade 160 in three control modes.

In a first control mode, a gradually increasing clamping force isapplied to tissue disposed between the clamp arm 152 and the ultrasonicblade 160 prior to transmitting ultrasonic energy to the ultrasonicblade 160. The clamping force is increased from a minimum clamping forceF_(min) to a maximum clamping force F_(max) over a predetermined firstclamping time t_(c1) while the clamp arm is under displacement control.In an embodiment, the minimum clamping force F_(min) can be about zero,the maximum clamping force F_(max) can be selected from the range fromabout 5 lbs. to about 7 lbs., and the first clamping time t_(c1) can beselected from the range from about 1 sec. to about 4 sec.

A second control mode can occur immediately after the first control modeand it occurs before transmission of ultrasonic vibrations to theultrasonic blade 160. As shown, the second control mode includesmaintaining the maximum clamping force F_(max) for a predeterminedsecond clamping time t_(c2) while the clamp arm is under displacementcontrol. The second clamping time t_(c2) can be selected from the rangefrom about 0.75 sec. to about 2 sec. (e.g., about 1 sec). The relativelyhigh maximum clamping force F_(max) can ensure that the middle layer oftissue (e.g., 2004) separates, as illustrated in FIG. 20B.

A third control mode can occur immediately after the second control modeand it can occur during transmission of ultrasonic vibrations to theultrasonic blade 160. As shown, the third control mode includes reducingthe clamping force to a treatment clamping force F_(treat) that isbetween the minimum clamping force F_(min) and the maximum clampingforce F_(max) (e.g., about half of the maximum clamping force F_(max)).The third control mode also includes maintaining the treatment clampingforce F_(treat) for a predetermined treatment time t_(t). In anembodiment, the treatment clamping force F_(treat) can be selected fromthe range from about 3 lbs. to about 5.5 lbs. and the treatment timet_(t) can be about 18 sec. The reduction in clamping force from themaximum clamping force F_(max) to the treatment clamping force F_(treat)and maintenance of the treatment clamping force in load control over theduration of the treatment time t_(t) can ensure that the clamping forceis sufficient to ensure good contact between the ultrasonic blade 160and the tissue without applying a relatively high clamping force thatcan tend to cause tissue sticking to the ultrasonic blade 160.

During the treatment time t_(t), a peak amplitude of ultrasonicvibrations transmitted to the ultrasonic blade 160 can be varied betweena minimum ultrasonic amplitude A_(min) and a maximum ultrasonicamplitude A_(max). As shown, an ultrasonic amplitude A₁, between theminimum ultrasonic amplitude A_(min) and the maximum ultrasonicamplitude A_(max), can be transmitted to the ultrasonic blade 160immediately after the second clamping time t_(c2) for a first portiont_(t1) of the treatment time t_(t). The minimum ultrasonic amplitudeA_(min) can be transmitted to the ultrasonic blade 160 immediately afterthe first portion t_(t1) of the treatment time t_(t) for a secondportion to of the treatment time t_(t). In an embodiment, the minimumultrasonic amplitude A_(min) can be about 50% of A_(max), and theultrasonic amplitude A₁ can be selected from the range from about 80% toabout 100% of A_(max). In an embodiment, A_(max) can be about 77 μm. Inan embodiment, t_(t1) can be about 1 sec. and t_(t2) can be about 16sec.

The first and second portions t_(t1) and t_(t2) of the treatment timet_(t) can extend over the majority of the treatment time t_(t). Theintermediate ultrasonic amplitude A₁ and the first portion t_(t1) of thetreatment time t_(t) can be configured to rapidly heat the tissue to atemperature sufficient to form the coagulum 2010 and begin ultrasoniccutting of the coagulum 2010. The minimum ultrasonic amplitude A_(min)and the second portion t_(t2) of the treatment time t_(t) can beconfigured to ensure that the extent of the coagulum 2010 is sufficientand continue cutting the tissue.

The maximum amplitude A_(max) can be transmitted to the ultrasonic blade160 immediately after the second portion t_(t2) of the treatment timet_(t) for a third portion t_(t3) of the treatment time t_(t). Themaximum ultrasonic amplitude A_(max) and the third portion t_(t3) of thetreatment time t_(t) can be configured to ensure that the tissue iscompletely cut. In an embodiment, t_(t3) can be about 1 sec.

FIG. 22 illustrates another exemplary embodiment of a treatment protocolfor inhibiting tissue sticking to an ultrasonic surgical instrument.Part A of FIG. 22 presents clamping forces applied to tissue by theclamp arm 152 as a function of time. Part B of FIG. 22 presentscorresponding amplitudes of ultrasonic vibrations delivered to theultrasonic blade 160 as a function of time. As discussed below, thecontrol system 39 can implement the treatment protocol such that aclamping force applied to tissue is varied during transmission ofultrasonic vibrations to the ultrasonic blade 160 in four control modes.

In a first control mode, a gradually increasing clamping force isapplied to tissue disposed between the clamp arm 152 and the ultrasonicblade 160 prior to transmitting ultrasonic energy to the ultrasonicblade 160. The clamping force can be increased from a minimum clampingforce F′_(min) to a treatment clamping force F′_(treat) over apredetermined first clamping time t′_(c1) while the clamp arm is underdisplacement control. The treatment clamping force F′_(treat) can be aclamping force that is between the minimum clamping force F′_(min) and amaximum clamping force F′_(max). In an embodiment, the minimum clampingforce F′_(min) can be about 2.5 lbs., the treatment clamping forceF′_(treat) can be selected from the range from about 3 lbs. to about 3.5lbs., and the maximum clamping force F′_(max) can be about 5.5 lbs.

A second control mode can occur immediately after the first control modeand it can occur before transmission of ultrasonic vibrations to theultrasonic blade 160. As shown, the second control mode includesmaintaining the treatment clamping force F′_(treat) for a predeterminedsecond clamping time t′_(c2) while the clamp arm is under displacementcontrol. The treatment clamping force F_(treat) can be configured toseparate the middle layer of tissue (e.g., 2004), as illustrated in FIG.20B.

A third control mode can occur immediately after the second control modeand it can occur during a portion of a treatment time t′_(t) duringwhich ultrasonic vibrations are transmitted to the ultrasonic blade 160.As shown, the third control mode includes increasing the clamping forcefrom the treatment clamping force F′_(treat) to the maximum clampingforce F_(max) and maintaining the maximum clamping force F′_(max) for apredetermined first portion t′_(t1) of the treatment time t′_(t) underload control. In an embodiment, the treatment time t′_(t1) can be about0.5 sec.).

Concurrently, an ultrasonic vibration amplitude A′₁ between a minimumultrasonic vibration amplitude A′_(min) and a maximum ultrasonicvibration amplitude A′_(max) can be transmitted to the ultrasonic blade160. The increase in clamping force from the treatment clamping forceF_(treat) the maximum clamping force F_(max) and maintenance of themaximum clamping force F_(max) in load control over the first portion ofthe treatment time t′_(t1) can ensure that the clamping force separatesthe middle layer 2004. The relatively moderate ultrasonic vibrationamplitude can be selected to provide coagulation of tissue while alsoreducing the likelihood of tissue sticking while the clamping force ishigh.

A fourth control mode can occur immediately after the third control modeand it can also occur during a portion of a treatment time t′_(t) duringwhich ultrasonic vibrations are transmitted to the ultrasonic blade 160.As shown, the third control mode includes decreasing the clamping forcefrom the maximum clamping force F′_(max) to the treatment clamping forceF′_(treat) and maintaining the treatment clamping force F′_(treat) for apredetermined second portion t′_(t2), third portion t′_(t3), and fourthportion t′_(t4) of the treatment time t′_(t) under load control. In anembodiment, t′_(t2) can be about 0.75 sec., t′_(t3) can be about 16sec., and t′_(t4) can be about 1 sec.

Concurrently, the amplitude of ultrasonic vibrations transmitted to theultrasonic blade 160 can be varied. As an example, an ultrasonicvibration amplitude A′₂, greater than the ultrasonic vibration amplitudeA′₁, can be transmitted to the ultrasonic blade 160 during the secondportion t′_(t2) of the treatment time t′_(t). Subsequently, anultrasonic vibration amplitude A′₃ can be transmitted to the ultrasonicblade 160 during the third portion t′_(t3) of the treatment time t′_(t),followed by the maximum ultrasonic vibration amplitude A′_(max) duringthe fourth portion t′_(t4) of the treatment time t′_(t). In anembodiment, the minimum ultrasonic amplitude A′_(min) can be about 50%of A′_(max), the ultrasonic amplitude A′₁ can be about 80% of A′_(max),the ultrasonic amplitude A′₂ can be selected from the range from about85% of A′_(max) to about 90% of A′_(max). In an embodiment, the maximumultrasonic amplitude A′_(max) can be about 77 μm.

The increase in ultrasonic vibration amplitude from A′₁ to A′₂ can beconfigured to ensure that coagulation of the tissue extends a sufficientdistance within the tissue to span the region to be separated. Theminimum ultrasonic vibration amplitude A′_(min) can be large enough toprovide tissue cutting. Thus, the decrease in ultrasonic vibrationamplitude from A′₂ to A′_(min) can be configured to ensure that tissuesticking does not occur while the ultrasonic blade 160 cuts the tissue.The increase in ultrasonic vibration amplitude from A′_(min) to A′_(max)can be configured to ensure that the tissue is severed by the end of thetreatment t′_(t) time.

b. Tissue Treatment Protocols for Inhibiting Clamp Pad Damage

As noted above, in robotic surgery, a user 12, 12′ can have less directhaptic feedback compared to traditional manually-powered surgicalinstruments. This lack of haptic feedback can result in uncertaintywhether tissue transection has completed. Thus, a user 12, 12′ can taketime to rotate the surgical instrument, while clamped and ultrasonicvibrations are transmitted to the ultrasonic blade 160, to visualize andverify the seal formed by the surgical instrument 100. However, in thecircumstance where tissue transection is completed and the clamp arm 152is fully closed, the clamp pad 154 can contact the vibrating ultrasonicblade 160. If left in contact with the clamp pad 154 for an extendedduration, the ultrasonic blade 160 can cut and/or burn the clamp pad154. Depending upon the severity of damage, it can be necessary toreplace the clamp pad 154, incurring time and expense. Accordingly,embodiments of the control system 39 can be configured to inhibit damageto the clamp pad 154 during use of the ultrasonic surgical instrument100.

As an example, the control system 39 can monitor the clamp force exertedon the tissue (e.g., by sensing the torque applied to motors coupled tothe drive system drive discs 220, 240, 260). When cutting and sealing oftissue is complete, the control system 39 can cause an audio and/orvisual indication (e.g., an audible tone) to be provided to signal auser 12, 12′ that transection is complete and to relax pressure on theultrasonic blade. As an example, the controller 30 can include one ormore audio and/or video components in communication with the controlsystem 39 and configured to provide the audio and/or visual indication(e.g., display 34).

Under the circumstance where the ultrasonic blade 160 is left in contactwith the clamp pad 154 for greater than a predetermined time after theaudio and/or video indication is provided, the control system 39 can beconfigured to further adjust at least one of the clamping force and theamplitude of the ultrasonic vibrations transmitted to the ultrasonicblade 160. As an example, when the predetermined time is exceeded, thecontrol system 39 can command the clamp arm 152 lower the clampingforce. This can allow a user to continue to transmit ultrasonicvibrations to the ultrasonic blade 160 with a lighter clamping force,improving the feel and/or responsiveness of the user's experiencewithout damaging the clamp pad 154.

c. Tissue Treatment Protocols for Applying Tension to CompleteTransection

It can be beneficial when employing ultrasonic surgical instruments,such as surgical instrument 22, to apply tension to complete tissuetransection. This tension can accelerate completion of tissuetransection, limit heat build-up in the ultrasonic surgical instrument100, and inhibit damage to the clamp pad (e.g., pad burn) due torelatively quick completion of tissue transection. However, it can bedifficult to apply slight tension using robotic surgical instruments, asthey can remain perfectly stable. Accordingly, embodiments of thecontrol system 39 can be configured to apply sufficient tension totissue near the end of tissue transection.

As an example, the control system 39 is configured to monitor theclamping force applied to tissue by the end effector 150 when operatingunder displacement control. When the tissue nears complete transection,the applied force increases as the clamp pad 154 begins to contact theultrasonic blade 160. After sensing that the clamping force reaches apredetermined clamping threshold, the control system 39 causes theultrasonic surgical instrument 100 to apply tension by slight movementsaway from the tissue (e.g., upwards and backwards). Alternatively oradditionally, the control system 39 can reduce the clamping pressure toprevent pad burn and heat accumulation, as discussed above. Either orboth of these operations can be performed immediately upon sensing thatthe clamping force reaches the predetermined clamping threshold or aftera predetermined time delay. Furthermore, either or both of theseoperations can be configurable by the user 12, 12′ using the controlsystem 39 and can be activated, turned off, or modified (e.g., thepredetermined clamping threshold, the predetermined delay, etc.).

d. Tissue Treatment Protocols for Maintaining Constant UltrasonicAmplitude

As discussed above, embodiments of the ultrasonic surgical instrument100 can be configured to allow articulation of the end effector 150,such as bending, using the articulation section 130. As an example, anarticulation angle of the end effector 150 with respect to alongitudinal axis of the ultrasonic surgical instrument 100 can becontrolled by rotation of the drive shaft 244. However, as thearticulation angle increases, ultrasonic vibrations transmitted to theultrasonic blade 160 can become attenuated. Accordingly, embodiments ofthe control system 39 are configured to compensate for this attenuation.

In one aspect, the control system 39 is configured to measure thearticulation angle of the end effector 150. As an example, the controlsystem 39 can measure upon rotation of the drive shaft 244 in order tomeasure the articulation angle of the end effector 150. In anotheraspect, the control system 39 can receive input from a user 12, 12′employing the controller 30 to command articulation of the end effector150. In response, the control system 39 can be configured to scale thecommanded ultrasonic vibration amplitude based upon the measuredarticulation angle of the end effector 150 in order to compensate forultrasonic attenuation. The control system 39 can perform this scalingduring articulation of the end effector 150.

One exemplary scaling relationship between ultrasonic vibrationamplitude and articulation angle of the end effector 150 is illustratedin the plot of FIG. 23. As shown, ultrasonic vibration amplitudegenerally increases as the end effector articulation increases from aminimum articulation angle (e.g., about 0°) to a maximum articulationangle (e.g., about 45°), reflecting a greater degree of ultrasonicattenuation at high articulation angles as compared to low articulationangles. In certain embodiments, a rate of change of the ultrasonicamplitude can increase with articulation angle. As an example, theultrasonic vibration amplitude can be about 100% at about 0° and theultrasonic vibration amplitude can be about 141% at an articulationangle of about 45°. In alternative embodiments, the rate of change ofthe ultrasonic amplitude can be approximately constant (dashed line).That is, the ultrasonic amplitude can be directly proportional to theultrasonic amplitude.

It should be understood that the relationship between the ultrasonicvibration amplitude and the articulation angle of the end effector 150can adopt other forms, depending upon the configuration of theultrasonic surgical instrument 100. The form of this relationship can bedetermined empirically, theoretically, or combinations thereof.

C. Combination Ultrasonic and Radiofrequency Surgical Instruments

In further embodiments, the surgical instrument 100 can be configured toprovide tissue coagulation through application of radiofrequency (RF)energy alone or in combination with ultrasonic vibrations. RF energy isa form of electrical energy that can be in the frequency range of about200 kilohertz (kHz) to about 1 megahertz (MHz). As discussed in greaterdetail below, the instrument 100 can transmit low frequency RF energythrough tissue, which can cause ionic agitation, or friction, in effectresistive heating, thereby increasing the temperature of the tissue.Because a sharp boundary is often created between the affected tissueand the surrounding tissue, a user 12, 12′ can operate with a high levelof precision and control, without sacrificing un-targeted adjacenttissue. The low operating temperatures of RF energy can be useful forremoving, shrinking, or sculpting soft tissue while simultaneouslysealing blood vessels. RF energy can work particularly well onconnective tissue, which is primarily comprised of collagen that canshrink when subjected to heat.

In order to facilitate delivery of RF energy to tissue, the generator300 includes a power source and control module that is configured toprovide RF energy to one or more electrodes mounted to the end effector150. Examples of generators configured to drive the ultrasonictransducer 120 and RF electrodes are discussed in greater detail in U.S.Patent Publication No. 2017/0202609, entitled “Modular Battery PoweredHand-Held Surgical Instrument With Curved End Effectors HavingAsymmetric Engagement Between Jaw and Blade,” the entirety of which isincorporated by reference.

FIG. 24A illustrates a side view of an exemplary embodiment of an endeffector 2400 configured to deliver ultrasonic vibrations and RF energyto tissue. The end effector 2400 includes a jaw member 2402 and a shaft2404. The jaw member 2402 can pivot about pivot point 2406 and define apivot angle. In certain aspects, the pivot point 2406 can be similar tothe pair of arms 156 and the pin 170 discussed above.

FIG. 24B illustrates another side view of the end effector 2400 of FIG.24A with a partial cut away view to expose the underlying structure ofthe jaw member 2402 and an ultrasonic blade 2410. The ultrasonic blade2410 can be the same as ultrasonic blade 160 discussed above. Anelectrode 2412 is fixedly mounted to the jaw member 2402. The electrode2412 can be electrically coupled to an RF drive circuit contained withina portion of the generator 300 configured to deliver RF energy to theelectrode 2412 (e.g., RF drive circuit 702).

The electrode 2412 is configured to apply RF energy to tissue locatedbetween the jaw member 2402 and the ultrasonic blade 2410. FIG. 24C ispartial sectional view of the end effector 2400 exposing the ultrasonicblade 2410 and an embodiment of the electrode 2412 including right andleft electrodes 2412 a and 2412 b, respectively. The jaw member 2402 andthe ultrasonic blade 2410 can be wider at a proximal end and narrower ata distal end. Also, the jaw member 2402 and the ultrasonic blade 2410can define more curvature at a distal end relative to the proximal end.A soft, electrically insulating pad 2414 can be disposed between thefirst and second electrodes 2412 a, 2412 b. In one aspect, theelectrically insulating pad 2414 can be located adjacent to a highdensity polymeric pad 2416 to prevent the ultrasonic blade 2410 fromshorting the electrodes 2412 a, 2412 b. In one aspect, the pads 2414,2416 can be formed from polytetrafluoroethylene (PTFE) polymers andcopolymers. Heat generated by the current flowing through the tissue canform hemostatic seals within the tissue and/or between tissues and thusmay be particularly useful for sealing blood vessels, for example.

In an embodiment, the end effector 2400 can be configured for bipolar ormonopolar operation. During bipolar operation, current can be introducedinto tissue by the electrode 2412 and returned from the tissue by theultrasonic blade 2410. During monopolar operation, current can beintroduced into the tissue by the electrode 2412 and returned through areturn electrode (e.g., a ground pad) separately located on a patient'sbody.

The RF energy can be in a frequency range described in EN60601-2-2:2009+A11:2011, Definition 201.3.218—HIGH FREQUENCY, theentirety of which is incorporated by reference. For example, thefrequency in monopolar RF applications can be typically restricted toless than about 5 MHz. However, in bipolar RF applications, thefrequency can adopt any desired value. Frequencies above 200 kHz can beused for monopolar applications in order to avoid the unwantedstimulation of nerves and muscles that can result from the use of lowfrequency current. Lower frequencies can be used for bipolarapplications if a risk analysis shows the possibility of neuromuscularstimulation has been mitigated to an acceptable level. In general,frequencies above 5 MHz can be avoided in order to minimize problemsassociated with high frequency leakage currents. Higher frequencies can,however, be used in the case of bipolar applications. In certainembodiments, 10 mA can be a lower threshold of thermal effects ontissue. Further discussion of embodiments of the generator 300 and theend effector 2400 can be found in U.S. Patent Publication No.2017/0202609, entitled “Modular Battery Powered Hand-Held SurgicalInstrument With Curved End Effectors Having Asymmetric EngagementBetween Jaw and Blade,” the entirety of which is incorporated byreference.

a. Treatment Protocols Utilizing Motor Torque for Maintaining TreatmentForce and Selective Delivery of RF Energy to Tissue

When using electrically-powered surgical instruments for delivery of RFenergy to tissue, it can be desirable to inhibit delivery of RF energyto tissue before the clamping force applied to the tissue reaches apredetermined range. When the clamping force is within this range and RFenergy is subsequently delivered to the tissue, the outer layer 2002 andinner layer 2006 can be properly sealed even while the tissue thicknessdynamically changes (e.g., decreases).

In non-powered surgical instruments, a large wave spring can employed tocompensate for variations in tissue thickness to apply the clampingforce within the predetermined range. However, in powered surgicalinstruments, where actuation of the end effector is driven by motors,this spring can be very difficult to control. Accordingly, embodimentsof present disclosure can provide powered surgical instruments in whichthe wave spring is omitted. The control system 39 can be configured toimplement treatment protocols that achieve clamping forces within apredetermined range by selectively controlling closure of an endeffector under either displacement or load control. In this manner, auser can employ powered surgical instruments for relatively delicatework such as spread dissection and tissue manipulation.

FIG. 25 is a flow diagram illustrating an exemplary embodiment of amethod 2500 including operations 2502-2514 for fine control of closureof an end effector to achieve a clamping force within a predeterminedrange using motors, instead of, for example, a wave spring. Embodimentsof the method 2500 are discussed in detail below in the context of therobotic surgical system 10 employing an ultrasonic surgical instrument100 using the end effector 2400. However, as noted above, the disclosedembodiments can also be utilized with hand-held powered surgicalinstruments as well. Additional embodiments of the method 2500 can omitone or more of the operations illustrated in FIG. 25 or add additionaloperations and the operations can be performed in a different order thanthose illustrated and described without limit.

In operation 2502, the user 12, 12′ can employ the controller 30 tocommand the jaw member 2402 to adopt the home position. In general, thejaw member 2402 is configured to move between an open position and aclosed position. In the open position, a degree of closure of the jawmember 2402 can be approximately 0%, while in the closed positon thedegree of closure of the jaw member 2402 can be approximately 100%. Forease of reference herein, the open position will be assumed as the homeposition. However, it will be understood that the open position can beany predefined location between and including the open position and theclosed position.

In operation 2504, the user 12, 12′ can employ the controller 30 tocommand the jaw member 2402 to adopt a selected degree of closure.

In general, movement of the jaw member 2402 under position control usesa received position command as a target set point without considerationof the force applied to the tissue as a result of such a movement.Moving the jaw in this manner can be advantageous because when thetissue is relatively thin because a low degree of closure can result inapplication of clamping force less than a predetermined minimum clampingforce F_(min) (e.g., a clamping force lower than desired for delivery ofRF energy to the tissue). However, moving the jaw in this manner is notadvantageous if the tissue is relatively thick because even a low degreeof closure can result in application of a clamping force higherexceeding a predetermined maximum force F_(max) (e.g., a clamping forcegreater than desired for delivery of RF energy to the tissue). F_(min)and F_(max) therefore represent a desired range of clamping forceapplied to the tissue for delivery of RF energy to the tissue.

In operations 2506 and 2510, the control system 39 determines whetherthe received command is executed in position control. As shown, inoperation 2506, the control system 39 determines if the degree ofclosure is less than a threshold closure (e.g., about 90%). If so, themethod 2500 moves to operation 2510. In operation 2510, the controlsystem 39 determines if a torque of a motor controlling displacement ofthe jaw member 2402 is greater than a threshold torque τ_(min). In thiscontext, torque can be used to approximate a measure clamping force. Asan example, an amount of torque applied by a motor controllingdisplacement of the jaw member 2402 (e.g., a motor operable to rotatethe drive shaft 264) can be correlated to the clamping force applied tothe tissue by the jaw member 2402. Thus, τ_(min) can be correlated toF_(min). This torque check can ensure that, even if the degree ofclosure is relatively low, the clamping does not exceed F_(max). Such acircumstance can arise if the tissue is relatively thick and the jawmember 2402 can contact the tissue with relatively little closure. Ifthe motor torque measured by the control system is less than thethreshold torque τ_(min), representing application of a relatively lowclamping force to the tissue, the method 2500 can move to operation2512, where closure of the jaw member 2402 is controlled under positioncontrol.

Alternatively, if either the degree of jaw closure is greater than thethreshold torque or the motor torque is greater than the thresholdtorque τ_(min), the method 2500 can move to operation 2514. In operation2514, control of the jaw member 2402 is performed in load control toachieve a clamping force at a preselected level from the range betweenabout F_(min) and F_(max). In load control, the control system 39employs measurements of the motor torque to control the clamping forceat preselected levels from the range between about F_(min) and F_(max),corresponding to τ_(min) and τ_(max). As an example, current drawn bythe motor operable to rotate the drive shaft 264 can be used to measureits motor torque.

An exemplary plot of motor torque as a function of displacement of thejaw member 2402 is illustrated in FIG. 26. As shown, for a given tissue,when the motor torque is less than τ_(min), the jaw member displacementis relatively low (e.g., less than δ₁). As a result, a degree of jawclosure can be below the threshold closure and the threshold torqueτ_(min) and the jaw member can be under displacement control. In thisregime, the motor torque can generally rise with increasing jaw memberdisplacement, representing movement of the jaw member 2402 towards theclosed position and rising clamping force. As discussed in greaterdetail below, RF energy delivery to the tissue is inhibited as theclamping force is lower than desired.

However, when the motor torque rises to τ_(min), control of thedisplacement of the jaw member 2402 can be performed by the controlsystem 39 under to load control. In this regime, the control system 39can ignore any displacement set points received from the user 12, 12′and instead closure of the jaw member 2402 can be controlled based upontorque set points (e.g., a torque between the minimum and maximumtorques τ_(min) and τ_(max)) to result in application of a clampingforce between F_(min) and F_(max)

It can also be desirable to limit application of RF energy to tissueunder circumstances where the end effector 2400 does not fully compresstissue disposed between the clamp arm 152 and the ultrasonic blade 160.If relatively high RF energy levels are employed on critical tissue,such as vessels, without substantially full compression, death canresult. In non-powered surgical instruments, such functionality can beachieved through a closure switch that confirms the surgical instrumentis fully closed.

To provide this functionality in electrically-powered surgicalinstruments without a switch, the control system 39 uses the degree ofjaw closure to determine whether or not a user 12, 12′ can deliverrelatively high RF energy levels to tissue. In one aspect, when jawclosure is under displacement control, the control system 39 can inhibitdelivery of RF energy to the tissue. In another aspect, when jaw closureis under load control and the jaw closure is less than fully closed, thecontrol system can permit delivery of RF energy at less than apredetermined threshold of RF energy. If a user 12, 12′ requestsdelivery of RF energy greater than the predetermined threshold RFenergy, the control system 39 can cause a notification (e.g., audioand/or visual) to be provided by the controller 30. In a further aspect,when jaw closure is under load control and the jaw closure is fullyclosed, the control system can permit delivery of RF energy greater thanthe predetermined threshold RF energy.

b. Treatment Protocols for Variation of Clamping Force Based Upon EnergyDelivered to Tissue

In further embodiments, the control system 39 can be configured to varycompressive forces applied to tissue clamped by an end effector basedupon the energy being delivered to the tissue (e.g., ultrasonicvibrations, RF energy, and combinations thereof). This flexibility canallow combination powered surgical instruments to perform “feathering”techniques employed to transect large tissues while ensuring that suchtissues are cauterized and any blood vessels are properly coagulated andsealed before transection.

In an embodiment, the control system 39 is configured to determine athickness of tissue to be transected. As discussed in detail below, adetermination of the tissue's relative thickness (e.g., relatively thinor relatively thick tissue) can be used to select whether compressiveforces are subsequently applied to the tissue under displacement (e.g.,velocity) control or under load control during a feathering treatment.

FIG. 27 is a plot of closing displacement δ_(c) of the jaw member 2402(Part A) and corresponding clamping force F_(c) (Part B) as a functionof time applied to tissue disposed between the jaw member 2402 and theultrasonic blade 160. With the tissue positioned in this manner, the jawmember 2402 can move towards the closed position under position controlat a first clamping velocity v_(c1) greater than a minimum clampingvelocity v_(min). As an example, the first clamping velocity v_(c1) canbe about 0.03 in./sec. and the minimum clamping velocity v_(min) can beselected from the range from about 0.005 in./sec. to about 0.01 in./sec.In certain embodiments, the first clamping velocity v_(c1) can beconstant, as illustrated by the constant slope of the displacement-timetrace shown in Part A (top) of FIG. 27.

As the jaw member 2402 contacts the tissue, the compressive force F_(c)applied to the tissue increases. When the compressive force F_(c)exceeds a clamping force threshold F_(o), a closure time t_(c) isrecorded. Assuming that the clamping velocity v_(c1) is constant, thecorresponding closure displacement δ_(c) can also be determined. Bycomparing the closure time t_(c) to a threshold time t_(o) or theclosure displacement δ_(c) to a threshold displacement δ_(o) a relativemeasure of tissue thickness can be made. As an example, if the closuretime t_(c) is less than the threshold time t_(o) or the closuredisplacement δ_(c) is less than the threshold displacement δ_(o) (CurveX), the tissue is determined to be thick because the jaw member 2402moves by a relatively small amount to contact the tissue. In contrast,if the closure time t_(c) is greater than the threshold time t_(o) orthe closure displacement δ_(c) is greater than the thresholddisplacement δ_(o) (Curve Y), the tissue is determined to be thinbecause the jaw member 2402 moves by a relatively large amount tocontact the tissue. In certain embodiments, the threshold displacementδ_(o) can be about 0.065 in., the thickness δ_(c1) can be about 0.06in., and the thickness δ_(c2) can be about 0.08 in.

FIG. 28 is a plot illustrating exemplary embodiments of the clampingvelocity v_(c) of the jaw member 2402, the clamping force F_(c) appliedto tissue, and relative amplitudes of various energy delivered to theend effector 2400 (e.g., ultrasonic vibrations and RF energy) as afunction of time for a thick tissue. As shown, the tissue can besubjected to a series of tissue treatments including clamping,feathering, and sealing. As discussed in detail below, the clampingtreatment is configured to grasp the tissue with the end effector 2400,the feathering treatment is configured to coagulate the tissue, and thesealing treatment is configured to further coagulate the tissue and cutthe tissue.

In the embodiment of FIG. 28, the tissue is assumed to be thick and theclamping and feathering treatments are performed under load control.When clamping under load control, the clamping force F_(c) can begin atapproximately zero and it can rise rapidly to a first treatment force F₁once the jaw member 2402 contacts the tissue. The first treatment forceF₁ can be selected between a minimum clamping force F_(min) and a secondtreatment force F₂. In certain embodiments, the second treatment forcecan be a local maximum for the clamping force F_(c) during the clampingand feathering treatments. As an example, the first treatment force F₁can be selected from the range between about 0.25 lbs. to about 0.5 lbs.(e.g., about 0.5 lbs.), and the second treatment force F₂ can beselected from the range from about 1 lb. to about 1.5 lbs., the maximumclamping force F_(max) can be about 2.5 lbs.

Delivery of energy to the end effector 2400 during the clampingtreatment is also illustrated in FIG. 28. In certain embodiments,delivery of RF energy to the electrode 2412 is omitted during theclamping treatment, while ultrasonic vibrations is transmitted to theultrasonic blade 2410. As shown, the ultrasonic vibrations can have afirst amplitude A₁ selected between a minimum ultrasonic amplitudeA_(min) and a maximum ultrasonic amplitude A_(max). As an example,A_(min) can be about 25% of A_(max), A₁ can be selected from the rangefrom about 60% of A_(max) to about 80% of A_(max).

During the clamping treatment, the clamping velocity v_(c) can increasefrom zero to a second clamping velocity v_(c2). As an example, thesecond clamping velocity v_(c2) can be a local maximum on the clampingvelocity during the clamping and feathering treatments and it can beabout 0.025 in./sec. In certain embodiments, the second clampingvelocity v_(c2) can be the same as the first clamping velocity v_(c1).The jaw member 2402 can move at second clamping velocity v_(c2)throughout the duration of the clamping treatment (e.g., until theclamping force F_(c) rises to the first treatment force F₁ and thefeathering treatment begins.

A first exemplary embodiment of the feathering treatment is alsoillustrated in FIG. 28. In general, the feathering treatment can beconfigured to coagulate tissue disposed between the jaw member 2402 andthe ultrasonic blade 160. As shown in FIG. 28, when the featheringtreatment is performed under load control, the clamping force F_(c) ismaintained at about a first treatment force F₁. In certain embodiments,the first treatment force F₁ is approximately constant through theduration of the feathering treatment. Similarly, the amplitude ofultrasonic vibrations is maintained at about A₁ and the RF energydelivered to the ultrasonic blade 160 is maintained at an approximatelyconstant level.

It can also be observed that the clamping velocity v_(c) can generallydecrease with time during the feathering treatment. This reduction inv_(c) can result from changes in the mechanical properties of the tissuedue to coagulation of the tissue by friction (e.g., mechanicalvibrations of the ultrasonic blade 2410) and RF energy delivered to thetissue from the electrode 2412. That is, the mechanical properties ofthe tissue can change over time during the feathering treatment.Accordingly, as time elapses under load control, a clamping velocityv_(c) can be sufficient to maintain the first treatment force F₁.Provided that v_(c) is greater than a minimum clamping velocity v_(min),the control system 39 can maintain the first treatment force F₁ for theduration of the feathering treatment. If the clamping velocity v_(c)falls to the minimum clamping velocity v_(min), the control system 39can perform feathering under load control according to a secondexemplary embodiment, discussed in greater detail below.

The sealing treatment can follow immediately after the featheringtreatment and it can be controlled by the control system 39 under loadcontrol. In general, the sealing operation can be configured to bothcoagulate and cut the tissue clamped by the end effector 2400. Thesealing operation begins in response to detection that a triggercondition is satisfied. In one embodiment, the trigger condition can bemovement of the jaw member 2402 to a predetermined degree of closure(e.g., the jaw member 2402 moves to a predetermined distance from theultrasonic blade 2410). The degree of closure of the jaw member 2402 canbe monitored by the control system 39 as discussed above. In anotherembodiment, the trigger condition can be a deviation from a velocity setpoint by a threshold amount or a clamping force F_(c) that rises to apredetermined percentage of a maximum clamping force F_(max), asdiscussed in greater detail below in the context of a third exemplaryembodiment of the feathering treatment under displacement (velocity)control.

In the sealing operation, the jaw member 2402 is moved to the closedposition and the clamping force increases from F₁ to the maximumclamping force F_(max). The clamping velocity v_(c) can rise sharply toa level greater than the first clamping velocity v_(c1) while theclamping force rises to F_(max) and subsequently decreases to aboutzero. That is, the jaw member 2402 does not move in closure once theclosed position is reached and the maximum clamping force F_(max) isapplied to the tissue. As discussed above, full closure of the jawmember 2402 can ensure that the middle layer 2004 of blood vessels areseparated. The maximum clamping force F_(max) can be a global maximumforce over all tissue treatment operations and it can be selected fromthe range from about 2.5 lbs. to about 3.6 lbs.

Concurrently, the amplitude of ultrasonic vibrations transmitted to theultrasonic blade 2410 and the RF energy transmitted to the electrodes2412 can be varied to facilitate coagulation and cutting of tissue. Asshown in FIG. 28, Part A, the amplitude of ultrasonic vibrations brieflyincreases to the maximum amplitude A_(max) to provide frictional heatingfor coagulating the tissue. Subsequently, the amplitude of ultrasonicvibrations decreases to a second amplitude A₂ greater than the minimumamplitude but less than the first amplitude A₁. As an example, A₂ can beabout 50% of A_(max). This decrease in ultrasonic vibration amplitudecan be synchronized with an increase in the amplitude of RF energy to amaximum value. This increase in RF energy can be configured to furtherpromote coagulation of the tissue. Subsequently, the ultrasonicvibration amplitude can increase to the maximum amplitude A_(max) asecond time to promote tissue cutting while the amplitude of RF energydecreases to zero.

Following the sealing operation, the jaw member 2402 can open to releasethe tissue. As shown in FIG. 28, Part B, the clamping force F_(c)decreases from the maximum clamping force F_(max) to about zero.Concurrently, as shown in FIG. 28, Part C, the velocity of the jawmember 2402 adopts a negative value, representing opening of the jaw.

A second exemplary embodiment of the feathering treatment under loadcontrol is illustrated in FIG. 29. In the first embodiment discussedabove (solid lines), the clamping velocity v_(c) remains above theminimum clamping velocity v_(min). In this second embodiment of thefeathering treatment, the clamping velocity v_(c) falls to a levelapproximately equal to v_(min). Under this circumstance, instead ofmaintaining the clamping force F_(c) at the first treatment force F₁throughout the feathering treatment, when the clamping velocity v_(c)falls to v_(min), the clamping force is increased to maintain theclamping velocity v_(c) at least equal to v_(min), as shown in thedashed lines of FIG. 29, Parts A and B. Upon determining that thetriggering condition is satisfied, the second embodiment of thefeathering treatment ends and the sealing treatment begins, as discussedabove.

A third exemplary embodiment of the feathering treatment under positioncontrol is illustrated in FIG. 30. As discussed above, position controlcan be employed when the tissue is determined to be thin. In the firstembodiment under load (solid lines), the clamping velocity v_(c) isallowed to fall while the first treatment force F₁ is maintained. Incontrast, this third embodiment of the feathering treatment initiallymaintains the clamping velocity v_(c) at a third clamping velocityv_(c3) while the clamping force F_(c) is allowed to change from thefirst treatment force F₁. The third clamping velocity v_(c3) can beapproximately constant. In certain embodiments, the third clampingvelocity v_(c3) can be the same as the first clamping velocity v_(c1).

The clamping velocity v_(c) can be kept constant or changed dependingupon the clamping force F_(c) resulting from v_(c3) during thefeathering treatment. If the clamping force F_(c) remains less than thesecond clamping force F₂, the control system 39 maintains the thirdclamping force v_(c3) throughout the feathering treatment. However, ifthe clamping force F_(c) rises to the level of the second clamping forceF₂ (e.g., at time t₂), the clamping velocity is reduced from the thirdclamping velocity v_(c3) to a fourth clamping velocity v_(c4) that isgreater than the minimum clamping velocity v_(min). The fourth clampingvelocity v_(c4) can be reached at time t₃ be sufficient to maintain theclamping force F_(c) at a level less than the second treatment force F₂(e.g., between the first treatment force F₁ and the second treatmentforce F₂) until the end of the feathering treatment at time t₄. Upondetermining that the triggering condition is satisfied, the secondembodiment of the feathering treatment can end and the sealing treatmentcan begin. In an embodiment, the time duration between time t₂ and timet₃ can be from the range from about 0.5 sec. to about 1.5 sec. Inanother embodiment, the time duration between time t₃ and time t₄ can befrom the range from about 1 sec. to about 4 sec.

As discussed above, the trigger condition can be a deviation from avelocity set point by a threshold amount. This trigger condition can besatisfied by deviation of the clamping velocity v_(c) from either thethird clamping velocity v_(c3) or the fourth clamping velocity v_(c4) bya predetermined threshold clamping velocity Δv_(c).

In another embodiment, the trigger condition can be the clamping forceF_(c) rising to a predetermined percentage of the maximum clamping forceF_(max).

III. Miscellaneous

It should be understood that any of the versions of instrumentsdescribed herein can include various other features in addition to or inlieu of those described above. By way of example only, any of theinstruments described herein can also include one or more of the variousfeatures disclosed in any of the various references that areincorporated by reference herein.

While the examples herein are described mainly in the context ofelectrosurgical instruments, it should be understood that variousteachings herein can be readily applied to a variety of other types ofdevices. By way of example only, the various teachings herein can bereadily applied to other types of electrosurgical instruments, tissuegraspers, tissue retrieval pouch deploying instruments, surgicalstaplers, surgical clip appliers, ultrasonic surgical instruments, etc.

In versions where the teachings herein are applied to an electrosurgicalinstrument, it should be understood that the teachings herein can bereadily applied to an ENSEAL® Tissue Sealing Device by EthiconEndo-Surgery, Inc., of Cincinnati, Ohio. In addition or in thealternative, it should be understood that the teachings herein can bereadily combined with the teachings of one or more of the following:U.S. Pat. No. 6,500,176 entitled “Electrosurgical Systems and Techniquesfor Sealing Tissue,” issued Dec. 31, 2002, the disclosure of which isincorporated by reference herein; U.S. Pat. No. 7,112,201 entitled“Electrosurgical Instrument and Method of Use,” issued Sep. 26, 2006,the disclosure of which is incorporated by reference herein; U.S. Pat.No. 7,125,409, entitled “Electrosurgical Working End for ControlledEnergy Delivery,” issued Oct. 24, 2006, the disclosure of which isincorporated by reference herein; U.S. Pat. No. 7,169,146 entitled“Electrosurgical Probe and Method of Use,” issued Jan. 30, 2007, thedisclosure of which is incorporated by reference herein; U.S. Pat. No.7,186,253, entitled “Electrosurgical Jaw Structure for Controlled EnergyDelivery,” issued Mar. 6, 2007, the disclosure of which is incorporatedby reference herein; U.S. Pat. No. 7,189,233, entitled “ElectrosurgicalInstrument,” issued Mar. 13, 2007, the disclosure of which isincorporated by reference herein; U.S. Pat. No. 7,220,951, entitled“Surgical Sealing Surfaces and Methods of Use,” issued May 22, 2007, thedisclosure of which is incorporated by reference herein; U.S. Pat. No.7,309,849, entitled “Polymer Compositions Exhibiting a PTC Property andMethods of Fabrication,” issued Dec. 18, 2007, the disclosure of whichis incorporated by reference herein; U.S. Pat. No. 7,311,709, entitled“Electrosurgical Instrument and Method of Use,” issued Dec. 25, 2007,the disclosure of which is incorporated by reference herein; U.S. Pat.No. 7,354,440, entitled “Electrosurgical Instrument and Method of Use,”issued Apr. 8, 2008, the disclosure of which is incorporated byreference herein; U.S. Pat. No. 7,381,209, entitled “ElectrosurgicalInstrument,” issued Jun. 3, 2008, the disclosure of which isincorporated by reference herein; U.S. Pub. No. 2011/0087218, entitled“Surgical Instrument Comprising First and Second Drive SystemsActuatable by a Common Trigger Mechanism,” published Apr. 14, 2011, thedisclosure of which is incorporated by reference herein; U.S. Pub. No.2012/0116379, entitled “Motor Driven Electrosurgical Device withMechanical and Electrical Feedback,” published May 10, 2012, thedisclosure of which is incorporated by reference herein; U.S. Pub. No.2012/0078243, entitled “Control Features for Articulating SurgicalDevice,” published Mar. 29, 2012, the disclosure of which isincorporated by reference herein; U.S. Pub. No. 2012/0078247, entitled“Articulation Joint Features for Articulating Surgical Device,”published Mar. 29, 2012, the disclosure of which is incorporated byreference herein; U.S. Pub. No. 2013/0030428, entitled “SurgicalInstrument with Multi-Phase Trigger Bias,” published Jan. 31, 2013, thedisclosure of which is incorporated by reference herein; and/or U.S.Pub. No. 2013/0023868, entitled “Surgical Instrument with Contained DualHelix Actuator Assembly,” published Jan. 31, 2013, the disclosure ofwhich is incorporated by reference herein. Other suitable ways in whichthe teachings herein can be applied to an electrosurgical instrumentwill be apparent to those of ordinary skill in the art in view of theteachings herein.

In versions where the teachings herein are applied to a surgicalstapling instrument, it should be understood that the teachings hereincan be combined with the teachings of one or more of the following, thedisclosures of all of which are incorporated by reference herein: U.S.Pat. Nos. 7,380,696; 7,404,508; 7,455,208; 7,506,790; 7,549,564;7,559,450; 7,654,431; 7,780,054; 7,784,662; and/or 7,798,386. Othersuitable ways in which the teachings herein can be applied to a surgicalstapling instrument will be apparent to those of ordinary skill in theart in view of the teachings herein.

It should also be understood that the teachings herein can be readilyapplied to any of the instruments described in any of the otherreferences cited herein, such that the teachings herein can be readilycombined with the teachings of any of the references cited herein innumerous ways. Other types of instruments into which the teachingsherein can be incorporated will be apparent to those of ordinary skillin the art.

It should be appreciated that any patent, publication, or otherdisclosure material, in whole or in part, that is said to beincorporated by reference herein is incorporated herein only to theextent that the incorporated material does not conflict with existingdefinitions, statements, or other disclosure material set forth in thisdisclosure. As such, and to the extent necessary, the disclosure asexplicitly set forth herein supersedes any conflicting materialincorporated herein by reference. Any material, or portion thereof, thatis said to be incorporated by reference herein, but which conflicts withexisting definitions, statements, or other disclosure material set forthherein will only be incorporated to the extent that no conflict arisesbetween that incorporated material and the existing disclosure material.

Versions described above can be designed to be disposed of after asingle use, or they can be designed to be used multiple times. Versionscan, in either or both cases, be reconditioned for reuse after at leastone use. Reconditioning can include any combination of the steps ofdisassembly of the device, followed by cleaning or replacement ofparticular pieces, and subsequent reassembly. In particular, someversions of the device can be disassembled, and any number of theparticular pieces or parts of the device can be selectively replaced orremoved in any combination. Upon cleaning and/or replacement ofparticular parts, some versions of the device can be reassembled forsubsequent use either at a reconditioning facility, or by a userimmediately prior to a procedure. Those skilled in the art willappreciate that reconditioning of a device can utilize a variety oftechniques for disassembly, cleaning/replacement, and reassembly. Use ofsuch techniques, and the resulting reconditioned device, are all withinthe scope of the present application.

By way of example only, versions described herein can be sterilizedbefore and/or after a procedure. In one sterilization technique, thedevice is placed in a closed and sealed container, such as a plastic orTYVEK bag. The container and device can then be placed in a field ofradiation that can penetrate the container, such as gamma radiation,x-rays, or high-energy electrons. The radiation can kill bacteria on thedevice and in the container. The sterilized device can then be stored inthe sterile container for later use. A device can also be sterilizedusing any other technique known in the art, including but not limited tobeta or gamma radiation, ethylene oxide, or steam.

Having shown and described various embodiments of the present invention,further adaptations of the methods and systems described herein can beaccomplished by appropriate modifications by one of ordinary skill inthe art without departing from the scope of the present invention.Several of such potential modifications have been mentioned, and otherswill be apparent to those skilled in the art. For instance, theexamples, embodiments, geometric s, materials, dimensions, ratios,steps, and the like discussed above are illustrative and are notrequired. Accordingly, the scope of the present invention should beconsidered in terms of the following claims and is understood not to belimited to the details of structure and operation shown and described inthe specification and drawings.

What is claimed is:
 1. A surgical system, comprising: an end effectorhaving an ultrasonic blade and a clamping element, the ultrasonic bladeconfigured to receive ultrasonic vibrations from an ultrasonictransducer and the clamping element configured to clamp and treat tissuedisposed between the clamping element and the ultrasonic blade asultrasonic vibrations are applied to the tissue from the ultrasonicblade; a shaft assembly having a longitudinal axis and the end effectordisposed at a distal end thereof, wherein the shaft assembly includes anarticulation section operable to deflect the end effector away from thelongitudinal axis at an articulation angle between a minimumarticulation angle of about 0 degrees when the end effector is alignedwith the longitudinal axis of the shaft assembly, to a maximum non-zeroarticulation angle when the end effector is not aligned with thelongitudinal axis of the shaft assembly; an interface assembly havingone or more drive shafts coupled to the end effector and the shaftassembly configured to drive movement of the end effector and the shaftassembly; and a control system including at least one processorconfigured to determine the articulation angle of the end effector andto control an amplitude of ultrasonic vibrations received by theultrasonic blade such that the amplitude increases with an increase inthe articulation angle of the end effector.
 2. The system of claim 1,wherein the control system is configured to measure rotation of a firstdrive shaft that is operable to adjust the articulation angle of the endeffector.
 3. The system of claim 2, wherein the control system isconfigured to control the amplitude of the ultrasonic vibrations basedupon the measured rotation of the first drive shaft.
 4. The system ofclaim 3, wherein the control system is configured to control theamplitude of the ultrasonic vibrations during articulation of the endeffector.
 5. The system of claim 1, wherein the control system isconfigured to control a rate of change of the amplitude of theultrasonic vibrations with respect to the articulation of the endeffector between the minimum and maximum articulation angles.
 6. Thesystem of claim 5, wherein the rate of change of the amplitude isapproximately constant between the minimum and maximum articulationangles.
 7. The system of claim 5, wherein the rate of change of theamplitude varies between the minimum and maximum articulation angles.